This tutorial takes no time and is super easy.
Apps needed:
-superimpose
-phonto
Open superimpose and add the image you want. Remember to change the constraints to 2:3 for the size of a cover.
Once the image is how you want it add the texture below.
Texture:
The texture should already be 2:3 but make sure it is just in case. Hit the transform button then the gears and lastly select hard light.
Your image should look like the example at the top. Merge and save to camera roll.
Open in phonto and add your title.
If you have any questions comment below and I'll get back to you!