Thread:KusaNin/@comment-27375020-20190703041535/@comment-25156300-20190703230744

Any art program will work. MS Paint, Photoshop, Paint Tool SAI, etc.

Basically, you would be just tracing the outline to make your own separate shape. You can then scrap the base image you were tracing and just fill your new shape with whatever color you want. After that, paste the kanji, or add a text box for it, if the program you use has text boxes.