how can I make friends?

This sounds like me. The best way to cultivate friendships with other people is to meet people who share your interests. That way, you have a starting point- you can talk about that interest as you slowly get to know each other better. You'll have a TON of people that won't ever really make it past that stage. But you'll get those few that you get to know on a deeper level.

Do you have any kind of activities, communities, etc., where you might meet people with something in common with you? A religious group, a workplace, a hobby gathering, etc.?

It's very important to have face-to-face friendships because there are some things that long distance friends can't do; however, I've found it rewarding to go onto websites for things that I like. For instance, if you like books, try Goodreads. If you like anime, try MyAnimeList. Stuff like that. Pick a hobby or interest and find a website for it, and be friendly and discuss your favorite things with people online. Be careful ,don't give out personal info, especially not early on, and eventually voice call with people (maybe on Discord) to get to know them better and to be more confident that they are who they say they are. There are some people who have the idea they'll find a girlfriend or boyfriend on the internet, so keep an eye out for the signs - if someone is ONLY talking to people of the opposite gender, or if they're acting too friendly too fast, or if they're asking you for pictures or Facebook... steer clear of people like that. But yeah, even though I've had some lousy experiences with people online, just like in real life, i have made a couple really wonderful friendships online.

It's not a replacement for real life friendships. There's all kinds of needs and friendships. But they are real people and you can meet people you'd never have known before. Don't give up looking for real life people though, you need them too!

Good luck