Huawei screen magnifier / touch screen off?

I have a project in school where we have to sign a picture of our mobile phone on foil. Now this is annoying extremely when I put the foil on the phone and then attach with the foil pen and the picture is moved the whole time because the pen is recognized as a finger. Does anyone have any suggestions here? Thanks in advance! (Have a Huawei mate 10 lite)

Print it out, anyway, is not so great, if one exerts selective pressure on his display. Can you also like to explain to your teacher

OK thanks!