All applications are transmitted digitally to GIEK after completion by the applicant. That occurs whether a signature is attached or not. But GIEK must have a valid signature to initiate processing.
You can apply a signature in the following ways:
1) Digitally using BankID or BankID on mobile (note: not from Skandiabanken). You do this as you submit your application, just as you do with your online bank.
2) Print out a copy of your application (which you will receive automatically by email after submission), then sign it, scan it and send it by email.