This is a very popular thing when it comes to thumbnail creation as most of us like to feature our pretty faces without a background. Many spend a long time carefully cutting out or using magic eraser tools and then smoothing out afterwards. Some use paid services which granted have great software to do the job instantly such as Canva.
But if you want to do it in 5 secs for free then check out REMOVE.BG very simple to use just drag - drop - download all done in 5 secs.
You are welcome :)
Check out my channel for more tips
EUPC3 | ST4 Member