A signing credential in your SIM
Mobile-ID places cryptographic credentials in a special SIM supplied through a mobile operator. The phone can then be used for electronic identification and document signing, without the separate card reader and desktop software required by a physical ID-card method.
The Estonian method supports qualified electronic signatures under eIDAS. Its use of a SIM is a defining part of the setup: an ordinary mobile number alone is not the Mobile-ID credential needed for this signing journey.
Prepare the phone and Mobile-ID service
Have the phone containing your Mobile-ID SIM available when you are ready to sign. The service is PIN-protected, so be prepared to follow its requested authorization steps. Mobile-ID can participate in a workflow across devices, with the phone providing the identity and signing credential.
Authentication and signature approval are distinct uses of Mobile-ID. Read the purpose of the request before authorizing it, especially when the wider transaction involves both access to a service and approval of a document.
Check the SIM replacement requirement
The official service notice says Estonian operators are replacing Mobile-ID SIM cards and that existing supported SIMs must be replaced before 19 May 2027. Without replacement, the notice states that signing and authentication will stop working from that date. Contact your mobile operator for the applicable arrangements and consult the official Mobile-ID information when preparing your service.
Finish signing in Nota Sign
Review the document in Nota Sign, fill in the required fields and proceed with the configured Estonian Mobile-ID method. Complete the requested authorization using your phone, then finish the document workflow in Nota Sign. Keep the SIM-based credential available until the requested signing steps are complete.
