I don’t recommend making your own covers unless you’ve got skills in graphics design or no other option. You can get a cover from Fiveer for $5 most of the time.
I made this cover my mashing some free images together, altering them in ArtRage, adding some drawing in ArtRage, then pulling it into another program to alter the image more
with some filters which helped smooth out the lines and make it all feel more fluid. This is a
cover for a short story of mine, inside the collection Cabals of Blood.