The three types you will be offered
Almost every quote in India will be Mono PERC, bifacial, or TOPCon. Each suits a different roof and a different budget.
Mono PERC
The most common choice. Efficiency of 20 to 22 percent at a reasonable price, and it performs well in hot, dry conditions. For most homeowners this is the sensible default.
Bifacial
Absorbs light on both faces — direct light on the front, reflected light on the back. On an open, reflective terrace it can add 10 to 15 percent generation. On a crowded roof, it adds little.
TOPCon
The newest and most efficient of the three, at 22 to 24 percent. It costs more per watt but produces more from the same area, which matters when roof space is the limit rather than budget.
How to choose
If budget is the constraint, Mono PERC. If roof area is the constraint, TOPCon. If you have a large, unshaded, reflective terrace, consider bifacial.