Need a more complete question please.
If it is couch cushion covers you need here are some good videos for you. If this is not what you wanted, give us another chance to help.
Here are some articles on Hometalk for couch cushion covers: https://www.hometalk.com/search/posts?filter=couch%20cushion%20covers
Use the old covers as a pattern for the new ones. Reuse or use new for the stuffing or foam that is in the cushions.
Are the cushions on the couch removable?
Are the covers on the old cushions removable?
Do the old covers have a zipper?
If not, to get them off, you will need to slit the stitches of the seam (not cut the seams) carefully with a seam ripper on one side of the cushion. After removing the cover away from the interior foam, you will then need to continue with the seam ripper, taking apart all the seams.
This will be time consuming , but in order that you can use the pieces of the old cover as patterns, cutting out adequate seam allowances will be required. Pressing each piece with an iron will help to get them as flat as possible before laying them down on the new fabric.
If you do not want to sew a zipper into the new covers, they can be sewn up on three sides, put back on the old foam insert, then hand stitched closed.