Basic phone case for OPPO A78. Has space on the back to insert a card. For people planning on doing this a lot, there is a version which has more space for easy card insertion.

Print with tree supports - build plate only - xy distance 0.3mm (Easier support removal). Layer height 0.12 looks nice, but anything should work. 100% Infill

I've found that it's easier to get in than out. If you want to remove the phone easier, you may want to consider scaling the model up by 0,5% before printing.