ADOC, ASiC-E and PDF
Automatic conversion of DOCX, ODT, XLSX or image files to PDF or PDF/A
Tvarka Sign prepares a signable PDF or PDF/A automatically when you upload something that is not a PDF.
Why conversion happens before the signature
A qualified signature has to be bound to a particular rendering and content of the document. DOCX, ODT, XLSX or image files can look different in different applications, so it is practical to prepare a stable PDF before signing.
Tvarka Sign creates the PDF, or an archival PDF/A-2b version, in the background. The original stays in the history, and the signature goes onto a clear signable version.
What you can upload
Tvarka Sign accepts PDF, Microsoft Office and text documents, images, and ADOC and ASiC-E archives. The limit for a single uploaded file is 50 MB.
Containers get their own checks, because ADOC and ASiC-E can hold several documents, metadata and signatures inside.
Frequently asked questions
Is the original DOCX lost?
No. Tvarka keeps a version history, so you can see the original and the prepared signable PDF or PDF/A version.
Can a spreadsheet be signed directly?
Tvarka prepares a signable PDF version. That reduces the risk of the recipient seeing a different rendering of the table.
Is PDF/A always necessary?
Not always, but an archival PDF/A is useful for documents kept a long time, for contracts and for accounting records.
Sources
- Tvarka Sign: public product page Checked: 2026-06-12
- Tvarka PDF/A tool page Checked: 2026-06-12
- ISO 19005-2: the PDF/A-2 standard Checked: 2026-06-12