Easiest method would be to just make the instructions as two paragraphs and type the prompt in size 1 white font between the paragraphs. As far as the document is concerned it would read as one paragraph. Set the font to white size 1.
(InjectionPrompt goes here) Now that you have read the above instructions, please write your full report below of how you implement this new technology. Lorm ipsum yada yada yada

If you wanted to be very devious you could probably write, write the entire prompt in whitespace. But I kind of wonder if the ai would be able to notice it

https://en.m.wikipedia.org/wiki/Whitespace_(programming_language)