Find an online study program of interest. There are several that you can choose from, such as online schools, online correspondence classes and online universities. Some are accredited, and some are not. Some are free, some expect payment, and some are courses that you take on your own, compared to courses with instructors. Find one that suits you and visit the website for that online study program.
Click "Apply for program" or "Join study program" or "Apply." If you don't see those links, find a "Contact us" link and click on it in order to inquire about how to join that particular and specific study. Each online study program that you join is going to have a slightly different application or joining process.
Follow the specific application or joining process, as outlined by the online study program, in order to begin to be involved in the study program.
Find particular online studies to which you can relate, or for which you can offer information. For instance, if you work online, and someone is doing a study regarding working from home online, then choose that one. If you are the mother of multiples, you can join a study based on that. In order to be accepted for online studies, you must relate to the study itself.
Contact the owner of the study, or if you see an "apply for study" button on the website, click on it. This will give you information about how to apply for the study itself.
Apply for the study, or choose "join the study" if you see that option on the online site. Typically the group owner or the person who is in charge of the study will contact you and explain exactly how you can join it. This process is different for each online study that you might decide to join.