Canvas does not handle financial transactions, nor does it require payments when creating a user or enrollment. If you are charging for a course, it's entirely up to you how you collect payments.
There is information about integrating Canvas with an SIS system, which includes how to generate users, courses, and enrollments with feed file, at https://community.canvaslms.com/t5/Canvas-Basics-Guide/What-are-SIS-Imports/ta-p/47 . There is information about both import formats and APIs at https://canvas.instructure.com/doc/api/file.sis_csv.html
I presume you using your own instance of Canvas? You will not have access to many of these tools and processes if you do not have administrator access.