I reposted one of the pics below. A portion of your tube is sitting under the bead (edge) of the tire, and is pushing it off the rim. The most common cause is poor installation, but, judging from the looks of your valve stem, riding under insufficient tire pressure may have contributed to the problem. You may find on deflating the tube that it is folded over.
Check the Park tool page on tire mounting: https://www.parktool.com/blog/repair...d-installation and also check a few videos: https://www.google.com/search?biw=14....0.HgKkjPRmbrw

The good news is that this problem will motivate you to learn one of the most basic and necessary skills related to owning a bike. You almost certainly don't have the tire levers that are recommended for removing (but not for installing) the tire. If you have some metal spoons or forks with flat handles and curved ends you can use those instead. DO NOT use a screwdriver or anything else with sharp edges. Some big box stores or hardware stores, and of course a bike shop would have tire levers for sale.