Hello!
First, the Mobee app is just the tip of the iceberg for this industry. There are folks who do this full time to support themselves, folks who just do this for the experiences (i.e. cruises) that they would not otherwise be able to afford, folks who do this to cover every-day expenses (i.e. oil changes), folks who do this for a little spending money, and everything in between. You can make of this what you want - though don't expect to get rich. Me? I teach high school full time and brought in a little less than $25K (not including reimbursements) last year.
I suggest you start by going to the "New Members" area of this forum. There is a tremendous amount of information there. Second, there is a list of companies (MSC's) linked at the bottom of this page - over 200 of them and all legitimate. I suggest registering with the "15 Most Discussed" first as they are all larger MSC's with work nationwide. Thereafter, as you have questions, just ask. This is a reasonably friendly crowd. Many will share insights with you - though there will be limits. You can also just read the forum. Most questions that you could come up with have been answered many times over on these pages.
Good Luck!!
Hard work builds character and homework is good for your soul.