I use Cozy.co to collect online rent from tenants that are interested in paying that way. If you use the free option, it will take a few days. You can pay for the accelerated service. I like Cozy for other reasons as well though, such as their credit checks and their refusal of "partial" rent payments, unlike Venmo, Paypal, etc.
Do you find that your tenants enjoy paying rent online? For me it's varied a bit from town to town. I.e. Hartford CT tenants aren't huge fans, but tenants in suburbs like windsor / windsor locks are more apt to do it.
I have used Venmo and it’s pretty simple