Joining any group your comfortable with, as others have said, is the #1.

One you can do from home is just start sending money to mutual aid requests you see on insta or wherever. Make it a weekly thing even if it's just a couple of dollars. There are also plenty of groups that operate mainly online, though they tend to be harder to get into for security reasons.

And honestly, being generally nice to random people is underrated. Never doubt how much better you can make a stranger's day by giving them a smile. Similarly, some of the best support I get is just from chatting with people, I've had so many crap days completely turned around because we had a seemingly meaningless conversation. I guess we're social creatures after all, so it's not too surprising.