How to Issue an Invoice and What Not to Forget

Quick Overview

• An invoice is not a separate legal term with a single universal list of required elements. Its mandatory content depends on whether it also serves as a commercial document, an accounting document, or a tax document.
• On commercial documents, a business owner must include, in particular, their name or business name, registered office, and identification details.
• A VAT payer must comply with the requirements set forth in the Value-Added Tax Act when issuing a tax document.
• It is also practical to include the account number, variable symbol, and due date on an invoice.
• A signature or stamp is generally not required for a standard invoice to be valid.

Are you in business and need to ensure your contracts, invoicing, or terms of cooperation are properly set up? Our attorneys will help you review the legal framework of your business relationship so that it is clear from the outset what the customer is paying for, when, and under what conditions.

Invoice vs. Tax Document

An invoice and a tax document are often the same thing. The terminology depends primarily on the purpose. We refer to a document as an “invoice” when it is issued by a person who is not a VAT payer. In this case, its primary function is to request payment and also to serve as proof of a sale (or the provision of a service). An invoice can also be used for accounting purposes by both parties as evidence of income or expenses.

An invoice becomes a tax document when it is issued by a VAT payer and serves as proof of tax payment. In this case, it must contain the same information as a standard invoice, but it must also include information on the VAT rate or the price per unit of goods excluding VAT.

Required Elements of an Invoice

The mandatory elements of an invoice vary depending on the document’s purpose. Different rules apply to a business document issued by an entrepreneur, to an accounting document, and the VAT Act specifies additional requirements for a tax document. In addition to the required information, it’s a good idea to include details that will make payment easier for the customer and simplify your record-keeping.

First and last name or company name

This information serves as the basic identification of the person or company issuing the invoice. Therefore, it must include the full first and last name or the official company name as registered in the Commercial Register (e.g., Dostupný advokát s.r.o.).

Registered office

Here, you must provide the complete address of the individual’s or company’s registered office. The address should include the street, house number, city, and ZIP code (V Jámě 699/1, Prague 1 — Nové Město, 110 00).

IČO

The Individual Identification Number (IČO) is a unique number assigned to a self-employed individual for identification purposes in state and financial registries. It is essential for legal transactions and communication with government institutions.

If you are self-employed, your invoice must include information about the registry in which you are registered, i.e., the Trade License Registry. If you are a company, your invoice must state that you are registered in the Commercial Registry, including the section and entry number.

Invoice Identification

Each invoice should have a unique number or code that distinguishes it from other invoices and helps you organize your accounting overall. However, this identification is especially important when you submit invoices to the tax office, for example.

For this reason, it is necessary to have a clearly defined and sequential system. The numbering system is not mandated by law, but it must be clear and continuous. It is therefore a good idea to choose a number sequence that reflects the invoice’s order and its date of issue—for example, 24042511. In this numbering sequence, we have the current date (April 25), the year (24), and the invoice serial number (11), which indicates that we have already issued ten invoices this year and this is the eleventh. You can reset the sequence number every month or year, or you may not need to reset it at all. However, it is essential to maintain continuity.

For larger companies, the invoice number often also includes a designation indicating the type of invoice (most commonly “FV” for an issued invoice), the billing department ( if the company has multiple departments), the customer’s name, and other necessary information. In all cases, however, the sequential number must be included.

Customer Information

This section should include basic information about the person to whom the invoice is issued. Specifically, the first and last name or company name, registered address, and business ID number.

Description of Goods or Services

Here, you must list all the services or goods covered by the invoice, including the name of the goods or services, quantity, unit price, and total price. Each item should be clearly described so there is no doubt about what was delivered.

The description should be sufficiently specific. Instead of a general term like “services,” it is therefore better to specify, for example, “graphic design work for September 2026” or “legal consultation on September 15, 2026.” Accurate identification of the services rendered not only aids accounting but also helps resolve any potential disputes regarding what was actually ordered and billed.

Payment Information

The invoice should include the total amount and the payment method. If you are requesting payment to a bank account, your account number should be included, as well as a variable symbol (if applicable) to identify the specific payment. You can use the invoice number as the variable symbol, for example.

Invoice Date

Enter the date on which you issued the invoice here. If you are a VAT payer, don’t forget to include the date of the taxable supply (DUZP). As a VAT payer, you should also keep in mind that you are required to issue an invoice within 15 days of providing the service or delivering the goods.

Invoice due date

This date indicates the deadline by which the customer must pay you for the goods or services listed on the invoice. By law, the invoice due date is set at a maximum of 30 days from the date of issuance, or 60 days if the transaction is between two businesses.

However, you may set the invoice due date to an earlier date at your discretion. The standard payment term is 14 days. For small businesses, however, a payment term of 7 days is not uncommon. In any case, it’s a good idea to agree on a shorter payment term with the customer in advance.

Signature Field

The signature field is not intended for the invoice issuer. Therefore, you do not need to worry that an invoice you issue without a signature will be invalid. This section is actually intended for the customer, or for the person who handles accounting on the customer’s behalf.

The Most Common Mistake When Issuing an Invoice

In practice, a common problem is that business owners automatically assume that all information listed in the invoicing software is required. In reality , it is important to distinguish between legally required elements and information that is merely practical. A typical example is the bank account number or variable symbol: these are very useful for payment, but they are not among the general legal requirements for every invoice.

Overdue Invoice—What to Do

Even if your invoice is error-free and includes a clearly stated due date along with payment instructions, this is no guarantee that the customer will pay it. Almost every business owner has encountered a similar problem, including us at Dostupný advokát. So let’s take a look at how to proceed in this situation:

1. Polite Reminder: First and foremost, it’s a good idea to politely remind the customer that you’ve sent them an invoice that is past due. These things happen all the time, and it’s usually just a misunderstanding on your part or the customer’s. If the customer does not respond to your notice within a few days, it’s a good idea to send another reminder.
2. Pre-litigation Notice: If the customer still does not respond, it is time to take stronger action in the form of a pre-litigation notice and a threat to resolve the matter in court. First, send the pre-litigation notice yourself, and if that fails, have a lawyer send it. In most cases, this step will result in payment of your invoice. After all, most people do not want to risk legal proceedings and paying attorney’s fees.
3. Filing a Lawsuit: The pre-lawsuit demand must be sent at least 7 days before filing a lawsuit. Therefore, if the customer does not respond to the pre-lawsuit demand, you should file a lawsuit against them within seven days.
4. Publicizing the Debtor: In addition to the lawsuit itself, it’s a good idea to alert other businesses and warn them about the delinquent payer. You can use various review sites or the Central Register of Debtors for this purpose. You should inform the debtor about this public disclosure.

Is the invoice past due and the debtor not responding? You don’t have to figure out on your own whether a reminder is sufficient, when to send a pre-lawsuit demand, or when it makes sense to go to court. We’ll review the debt, prepare the necessary legal steps, and, if needed, represent you in collecting it.

Summary

If you’re wondering how to issue an invoice, first determine whether the document must also meet the requirements for an accounting or tax document. The mandatory elements of an invoice vary depending on this. A business owner must correctly state their identification information and clearly label the document; for a VAT payer’s tax document, additional information required by the VAT Act must be included. It is also practical to include the account number, variable symbol, and due date. As a rule, an invoice does not need to be signed by hand. If the customer does not pay, start with a reminder; you can then issue a pre-litigation demand and, as a last resort, file a claim in court.