What do I do if I have two accounts signed into one phone
I’m signed into my iPhone 11 under two accounts, how do I sign out of both?
Apple Watch
You can only have one Apple ID in the main settings. You can use other IDs in subsections such as the App Store, or in Mail. So I guess I am not clear as to what makes you think you are signed in twice.
Here's how to do the main one:
Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac:
"You can sign out of iCloud on one of your devices, or you can sign out on all your devices to stop using iCloud."