my iPhone 7 plus don't have portrait.

I am assuming, from your post, that your iPhone 7 Plus is locked in landscape mode and you cannot get to its portrait mode. If my assumption is correct then you have locked your screen to landscape mode.

To unlock your screen orientation Open Control Panel by Swiping UP from the bottom edge of your screen (in your current screen orientation) and then tap on the lock icon (shown below).

This action should return your iPhone's ability to get back into Portrait mode as required by you.

Axel F.

If it doesn’t go into portrait mode open your control centre and click the lock which will make your phone be able to rotate.

also it is called rotation lock in settings