If I have a digital work book, what document do I need to add for that...?

As far as I understand, the question is about confirmation of insurance experience, without an employment book.

The above-mentioned issue is regulated by the Procedure for confirming the existing work experience for the purpose of pensions in the absence of a work book or relevant entries in it.

In the absence of a work book or relevant records in it, the length of service is established on the basis of other documents issued by the place of work, service, training, as well as archival institutions.