Our younger tenants all pay thru apartments.com (as mentioned above was cozy.co). We still take checks & cash from a few, mostly older tenants. Service works great BUT they hold money for 5-7 days. Not an issue for us, but might be for some. When we signed up, there were fewer services & cozy seemed like the best. I'd like to switch to one that sends us money quicker, but to change a bunch of tenants seems confusing & very much a hassle for us & them.
Some people use zelle but our bank doesn't have it. On venmo, we had a tenant start trying to pay via them, but with a same amount every month we were told that there would be a fee. I think it was 2% or something.