I've been making a few throw pillows (cushions if you are British) just recently and been looking for ways to close the back so they are still easily accessible for removing the insert and washing the cover, but I don't have any long zips right now (and I admit I've not yet ever sewn a zipper into a pillow cover) so I was looking for alternatives.
 
Here's how to sew snap tape to close a pillow back: https://so-sew-easy.com/pillow-back-sew-snap-tape/