How do I make sure my iPhone is locked?

How do I find out if my iphone is locked, or how do I make sure that it is locked before I go away and leave it to finish the download:

I am am trying to download the files from my iPhone to my account to back up my phone. I am using iOS 106.2, I think.

The directions say say to make sure that the phone is locked and on WiFi, but I don’t know how to make sure that my phone is locked.

I would appreciate any any help anyone can give me as I am really new at all this

Thank you for your help.