Now the 'proper' way is to sew it to some sort of base or mount. This often requires first hemming the edge to ensure it doesn't fray under tension. Or if it is little enough to be a bookmark you could use hemming table to stick it to a base bit of felt.
But what if it isn't bookmark material or you want to put it up on a wall or in a frame? Or you are like me and are too lazy to do the 'proper' way for something that is little? (I'm better on big stuff that takes years!).
So I have this little embroidery that needs to be mounted lest the fabric be wrinkly.
The first step is to sort the edges of the fabric out so they don't move or fray- particularly since this is two pieces of fabric with wadding in the middle. So I got my sewing machine out and- just kidding. This is a lazy job. Masking tape to the rescue!
Now for the board to mount the fabric on. Lots of two dollar/cheap shops now sell craft supplies and painting supplies and they carry canvas boards in a wide range of sizes from the very small (what I need) to very large (useful source if you want thick, non-bendy card for a project). Even better, the shop near me had 50% off. Score!
Your board should be at least 2cm smaller around for each edge to be able to fold the material over easily for taping.
Fold and tape over top and bottom.
If you are happy with things at this point, leave it be. I found the edges were showing so I very carefully cut off the excess using scissors. Don't cut too close to the front of the piece or the fabric will possibly fray on the front.
Now I will say that this is strictly for small, minor projects. I don't know how well it will hold up over years, nor do I know that the tape will or won't do anything to the material for a while. A little project like this that only took a day or so (well I did it over a few weeks but that's because I don't get to craft as much as I'd like) is possibly going to end up as part of a card or just stuck in a corner, it's not exactly heirloom work! If you have spent months or years on a project, it's worth spending the time and/or money to do or to get someone to do things right.
Hope this helps you do something with the pile of finished work- enjoy!