There are the follwoing documents required for Tax Preparation in India.
Permanent Account Number (PAN)
Aadhaar Number
Bank Information and Details of the Assessee
Any other investments proof under 80C, 80D, 80E and 80 TTA
Travel Bills
Tax Deducted at Source Documents (Form 16, Form 16A, Form 26AS
Rental Agreement
Bank Books Certificates
Click here to know more - Tax Preparation Services