UK visit visa from India

[logical_riz]

Hi, I am planning to apply for my mother's visit visa first time.
I would like to know what are the documents do I need from my mother's side as her main source of income is farming (all cash). Also how much money should I show in my uk account to make the application strong?
she is residing in Haryana, India.

I will be thankful if anyone can please reply.

thank you.