Can I use
Attach a signature meaning affix signature?
Which I suppose means signing.

Could I use affix/attach in case of fingerprints too?

Question

Can I use 
Attach a signature meaning affix signature?
Which I suppose means signing.

Could I use affix/attach in case of fingerprints too?

Answer

Is this in the context of an email? E.g. I’ve attached the document with my signature below.

I’ve never used “affix” in that manner, but I’m from the US, so it might be regional.