Hello,
I apologize, but I am a little confused on what the issue you are asking about is?
It will say Safari in the top left when you are currently using the Safari application, and will change to whatever application you switch to: i.e. Finder, Mail, etc.
You can access About This Mac from the menu in the top left of the screen, and it will give you information about the Mac and the version of macOS.
If you can clarify a bit, we may be able to help out,
C