Having beautiful banners custom made for your units elevates your army to the next level. In a way, especially for fantasy troops, it is the flying colours and vivid coat-of-arms imagery that makes your playing pieces be what they are, not just a heap of plastic. It is no coincidence that in many strategy games units are represented just by their unique standards.
If you are not the kind of person that can draw a human that is actually not just a stickman you might be afraid to try freehand painting. But his is actually a lot easier than you imagine.
First of all nobody expects you to just start on an empty canvas and by a few strokes of colour create a Mona Lisa. The trick is to start from a rough sketch and then to bring it step by step to a stage, where you have a drawing good enough to start colouring.
OK, it's better to use Adobe Illustrator or Clip Studio Paint but if you know how to use them, you know that already.
If the banner is mostly flat you can create the initial sketch from the previous method on your computer then print it out, paint it and glue to the model.