Legal notes

What a signature, a stamp and an invoice mean

This English version is a courtesy translation. The German version is legally binding and prevails in case of any difference.

Short and honest: what UCA PDF Editor does and what it does not. Not legal advice.

1. The signature in the app

A drawn or saved signature that you place in a PDF is a simple electronic signature within the meaning of Art. 3 No. 10 of the eIDAS Regulation (EU 910/2014). It is legally permitted and admissible as evidence (Art. 25 (1) eIDAS); the court freely assesses its evidential value. But:

• It is not a qualified electronic signature (QES) and not an advanced signature. We are not a trust service provider.
• It does not replace the written form (§ 126 BGB). Where the law requires the written form, you need a handwritten signature or a QES (§ 126a BGB). Examples: terminating an employment relationship (§ 623 BGB), a guarantee (§ 766 BGB), a fixed term in an employment contract (§ 14 (4) TzBfG), a consumer loan (§ 492 BGB). Notarial certification is not possible anyway.
• It meets the text form (§ 126b BGB) and declarations without a required form: offers, order confirmations, delivery notes, acceptance and handover reports, most contracts between businesses.

Optionally the app can add an integrity seal (a digital PDF signature with a device key). It only shows whether the PDF was changed afterwards. It is not a qualified seal and not a QES either.

2. The company stamp

In Germany a stamp has no legal effect of its own; there is no duty to use one. It shows that a document comes from the company. The company is bound only if the person who signs is authorised to represent it. That is why the app prints before the name what the company admin set for that person:

• i. A. (im Auftrag, on instruction): acts on instruction, without own power of representation;
• i. V. (in Vertretung): with a commercial power of attorney (Handlungsvollmacht, § 54 HGB);
• ppa. (per procura): with a registered Prokura (§§ 48 ff., § 51 HGB);
• no prefix: managing directors / owner.

"Verified" in the app means: the company admin confirmed the person and their signing authority. It is not a check by an authority or by us. Every person draws their signature themselves in the app; the admin approves it. Nobody can upload a signature for someone else.

It is not an electronic seal under eIDAS (that requires a qualified trust service).

3. Business letters

Letters and forms addressed to specific recipients must carry mandatory details (§ 37a HGB, § 35a GmbHG, § 80 AktG, § 125a HGB): the company name, legal form, registered office, register court and register number, and for a GmbH all managing directors. In a company account the app puts these details from the company data into the footer. The letter follows the DIN 5008 layout.

4. Invoices

• The template checks the mandatory fields of § 14 (4) UStG: name and address of supplier and recipient, tax number or VAT ID, date of issue, sequential invoice number, quantity and type of the supply, time of the supply, the price per tax rate, the tax rate and amount or a note on the tax exemption, § 19 UStG (small business), § 13b UStG (reverse charge). Small invoices up to 250 € (§ 33 UStDV).
• Invoice numbers in a company account come from the server without gaps, per company, kind and year, and are logged.
• E-invoice: since 1 Jan 2025 businesses in Germany must be able to receive e-invoices. A plain PDF invoice between businesses is only allowed during a transition: until the end of 2026, for businesses with a prior-year turnover of up to 800.000 € until the end of 2027. After that, B2B invoices need a structured format. The app can create ZUGFeRD / Factur-X (EN 16931): a PDF with the XML embedded. Invoices to consumers may still be sent as PDF.
• Retention (GoBD): the app is not an archive. Keep invoices unchanged and readable: 8 years (§ 147 AO, § 14b UStG). An e-invoice must be kept in its original format (XML).

5. Privacy

Your documents stay on your device. Companies conclude a data processing agreement with us (Art. 28 GDPR). Our server is in the USA (IONOS, Standard Contractual Clauses). Details: privacy policy.

Last updated: 23 October 2026