Employment Name change and Payment Evidence


I have a few queries on document and evidence.

#1. My first company name was changed after I relived from organization. Now Pay slip and Provident Fund statement has different name. I have a bank statement but doesn’t has the employer name. Please advise.
What will be required documents need to submit for name change?

#2. Payment Evidence
How many month pay slip need to submit for each organization ?

#3. Do I need to get employee reference letter from each organization or Can I provide experience certificate ?