There are 4 pre-drilled faucet holes on my sink. What are the holes for? (Kitchen faucet)

For single hole - With the single-hole faucet installation, there is no deck plate and accessory.

For two holes - One hole is for the single faucet and the second hole is reserved for accessories like
sprayers and soap dispensers.

For three holes - The center hole is for the faucet, the left hole is reserved for hot water handle and the
right hole is reserved for the cold water handle.

For four holes - Generally, the final hole is reserved for the sprayer or soap dispenser.