In my country (India), there are quite a few people who are illiterate and cannot affix signature using pen on paper. The law allows them to affix a thumbprint.

In my country (India), there are quite a few people who are illiterate and cannot affix signature using pen on paper. The law allows them to affix a thumbprint. A physical signature (or thumbprint) is a proof of intent. It can be witnessed. Some government documents require notarization (i.e., witnessed by a Notary public and signed/sealed) to lend the weight of genuinity. As an aside, it is a bit of an irony that even literate folks today have to use their thumbprint to unlock their iPhone or Android cellphones :) So, it has come full circle.