There will run into so many issues if you try to replace proper shipping labels with regular paper. Firstly, regular papers will tear easily, and the ink will smudge if exposed to moisture. So, on top of the paper, you will need to add a layer of tape to protect it. But because the sizes of shipping labels are larger than the size of normal tapes, you will need more than one piece of them on a label. It will take you a long time to cut it to the exact size. Moreover, if you try to do it quickly, things will not align properly and will end up looking very unprofessional.