hello, JSRangnick ^^
well im glad you came to deviantart, and no sorry there is no tag button here
. you can use 'keywords' when you submit your art so that people searching in the search bar will be able to find what you post, and thats about as close to 'tagging' as you can get haha.
Also one more thing, since you're on a really public website, you might want to be careful with how you address people here (aka calling me Cquiles and not Celeste because i prefer being called my username here) or displaying personal information like your schedule and year in school ^^. we have a noting system for those kinds of personal exchanges and you can note someone either by going to their profile page and looking for the 'note' button (upper right hand corner) or by going into your notes by hovering your mouse cursor over the arrow button next to 'submit' on the top bar of the deviantart webpage and clicking view all notes and make a new one from there.