Hi Antonia,

if I understand well, you are publishing your courses outside a Learning Management System (LMS, like Moodle). 

If you want, an easy option would be to open a free account on MoodleCloud.com and upload your courses there. There are some "quota" limits for free accounts, but you may have a look.

Alternatively, if you are publishing your course in a normal web site (let's say a WordPress web site or a total static one done in HTML) you may consider the option to use a social authentication (google facebook, so on) before providing them the courses.

Cheers, Fabio.