How do I restore Portrait Orientation Lock icon on my iPhone 15 control panel?

Attempting to help an iPhone 15 user utilize this feature, I did not realize that all the icons on the control panel were slightly muted, meaning that should one of them be "touched" it would remove it from the control panel. I did this with the Portrait Orientation Lock and it was removed from the control panel. What instructions are available to restore this feature and its icon?

[Re-Titled by Moderator]