Visit this link to download the template.
(Alternatively, right click and save the image from below.)
Download images to put on your sticker. I use Google and just search. Or, search for WordArt websites to add stylised text.
Personally, I use Canva, but there are better alternatives (such as GIMP). Open the background template, and insert all other images on top. Save your sticker.
You now have a sticker.
There are some down below which I have copied from other websites and some which I have made myself.
Have fun making stickers!
There are some websites which allow you to make a moving GIF sticker. How cool! One I have seen (not tested) is called ezgif.com.