This is a tutorial of one of my older edits, but I really likes and lots of people asked how I did it, so here you go!
1. Open up an eye picture in @picsart
(It's best to use a close-up picture like the one I used. Also, crop and adjust your photo to try and make sure that the eyeball is somewhere in the center or slightly to the right of the picture. The fire mask works best that way.)
2. Go to 'Masks' in the menu bar
3. In the 'Artistic' category, choose the 'Fire' mask
4. Tap the eraser icon on the top of the screen
5. Erase areas outside of the eyeball and on some parts of the eyeball too if you want to
6. That's it! Just save your image and you're good to go!