Apps needed:

Picsart  

1. Go to collage in picsart select your eight photos and then click a callage form I used  a size in 3:4 one of the very last ones arrange the photos any way you like.

2. Go to border and turn the thickness all the way down save when your finsihed.

Now you can add your text and filters and any other things your like.

I hope you enjoyed this tutorial! Happy editing lovelies!!