DSA is short for Direct Sales Agent. The person/organization known as DSA works as a referral agent. Whether for a bank, NBFC or other financial institution (FI).
The work of a DSA involves finding potential clients for the financial institutions he/she represents. For this, DSAs will look for people who are looking for a loan. These leads are then referred to the presented bank/NBFC/FI and the loan process gets started.
DSA is the link between the customer and the lender. He is supposed to ensure a basic check is done about the background, right documents are being submitted, as applicable to the guidelines of the loan provider.