You don’t. This girl doesn’t owe you her attention or time. If you ever make eye contact with her, and she isn’t giving you eyes that communicate “I think you’re attractive, come over to talk to me” then keep moving, friend. There are a ton of women out there, and many of them are interested in meeting men.
Eye contact. She smiles at you? Game on. She looks away quickly but doesn’t smile? She isn’t into you.
You don’t. Get into her circle of friends/interest first. If you can’t do that, then you have no chance of a long term relationship. Use shared or group activities to shine. Show your leadership values and personality. At the same time observe her for the same. If both of you are attracted to each other, then you can start talking about dates.
OP, most people in this instance are from Western Europe and ~half NA. I don’t think that you’ll get sensible advice on dating, marriage etc. here, given how heavily cultural those things are. (For others: OP is from India, check the profile.)
If you’re still willing to ask here, though, I encourage you to give a bit more context.
The question “How to propose a girl who doesn’t talk much to boys” sounds like it was either posed by an Indian person who doesn’t speak English all that well, or a bot.
Bots nowadays are rather good at generating grammatically sound sentences. The issue is usually not conveying meaning, but that doesn’t happen with OP.
If the issue is the lack of “to” after “propose”, keep in mind that verb regency can vary even among native speakers of a language. So while “propose a girl” might look incorrect for a Canadian or American, well, it’s on the same level as a Brit complaining because you forgot the U in “colour”.