Common Methods Of Sending Data To A Robot

Hi. I am wondering what are the common methods being used to send data to a robot. I have been using an attachment in an email or information in the body of an email as my method to trigger the robot and pass the needed data to it. But, are there other common ways being used? Also, does anyone use Web APIs to get data to the robot? Thanks.

SQL, httpRequest, shared folders, mail

Thanks so much. Question…could you please give a quick example of a httpRequest to make sure I understand what it is (is it the HTTP Request and SOAP Request activities under App Integration/Web? Thanks so much.