How do you add people to the people album?

You can only add people to the People album, if Photos recognized a face in some photo.

help.apple.com/iphone/11/#/iph9c7ee918c

Add more people. On a photo of someone you want to add, swipe up to see a thumbnail of that person (below People). Tap the thumbnail, tap Add Name, then enter the name, or tap it in the list if you see it (names in the list are from your Contacts app). Tap Next, then tap Done.

We cannot see your iPhone X, of course, but my iPhone X shows People, Places, and Related sections after a swipe up on a photo taken with the phone. People only shows if the Photos app has detected any faces in the photo.

It on the iPhone X swiping up initiates different responses than previous iPhone models. In this case it does not give me a thumbnail, it only shows related pics.