hiyo NightCrawler, the app (or site) they are using is called picsart, it's a editing app/site that lets you make thing like collages, edit, etc or you can just post pictures/art, it's completely safe just incase you aren't sure if you wanna check it out or not! enjoy :)))
if you look up certain aesthetics you would want (say for example): scene, emo, alt, grunge, y2k, cutecore, kawaii, fairycore, cottagecore, etc, you just have to keep scrolling for a little, and depending on what kind of aesthetic you look up you'll find more options
