Question for Contractors: How are you paid?

I'm working as an independent consultant/contractor. I've worked with a few clients. They always have their own system in place (e.g. Zenefits). I'm starting to work for some smaller clients (startup size) who have never paid a contractor before.

What service do you recommend I point them to? Or do you just give them bank account information and ask for a transfer?

PS. My clients and I are in the US.