Easiest way to make recurring payments to contractors

Hello BP!

Today I was curious about paying contractors. I have a contractor that is doing some financial analysis work for us right now and since we will be paying him every 2 weeks, I wanted to know what you thought the easiest way to pay was. 

We want to make sure that come tax time, we are all taken care of, but writing and sending a check every 2 weeks also does not seem efficient...

We have thought about using an app like Venmo to send money, but wonder if that leaves enough of a paper trail come tax time?

Any suggestions? 

Thanks, 

Chad