I can’t screenshot on my iPhone XR

So I was recently trying to screenshot on my iPhone XR and it wouldn’t let me and I was wonder if people who were having the same problem could respond ASAP or if anyone who works at apple for apple support could help me with this problem because I need to screenshot something very important to someone very important so please let me know ASAP if you have a solution or anything that you think could help me and possibly I could help you with one of your problems.