Well hex editing has nothing to do with coding for starters. Secondly you can use this :
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Run the exe, open w.e file you want, find the text you want to change. So to do this you just press Ctrl and F, click on Text string and type it in and convert to hex. Now this may not work for all types of files, and it could be because this is a basic editor. But it should be enough to get you started