Before 2021, GSA required a digital certificate to access their eOffer site (for vendors applying for a GSA schedule contract) or the eMod site (for current vendors wishing to change or modify their contract).
This is no longer the case. Now, GSA requires that you register for a FAS ID.
Obtain FAS ID Workflow - Navigate to eoffer.gsa.gov
Click on the Register Account button
Complete the form field (Name, email Company UEI number
Click Submit