So, to do something like this you’d want to make a custom overlay/background.
Some free apps you can try are Phonto, Picsart, Pixlr, IbisPaint
There’s no easy way for me to describe the process of making them on the forums. But, all of the apps have lots of tutorials on how to use their tools to create something. You can follow those tutorials to make something like these cards.
The other option would be to use text overlays and have them appear on the screen. This would be an option that doesn’t involve making a background/overlay. Dara has this tutorial on how to do that