This might help, from 2019….. Why must I choose new location for Pages documents? – https://discussions.apple.com/thread/250193663?sortBy=rank
Lucas1948
Well, I figured it out. Something unknown broke the connection between my iPhone and my iCloud account. The fix: I logged out of iCloud, restarted my iPhone, and logged back in. Problem solved.
I do have Apple laptops and an old iPad but am not a power user. Others here might have better info.
Ches