Employment Records: Post ITA questions

[Gurleenkaur2020]

1. For work experience letter, is the document need to be stamped? what it is on the letter head, but not stamped?
2. What if payslips for any employment is not available, but i have got my salary details included in the work experience letter? will it work?
3. Do we need to provide ITRs for each employment?

Thanks in advance