How to add link in Primary Navigation?

Hi there,

I'm not sure I fully understand what you mean.

Primary navigation is a navbar for the primary menu location. If you wish to add something beside it, outside the primary navigation bar menu, perhaps what you need is the generate_menu_bar_items hook.
https://docs.generatepress.com/article/generate_menu_bar_items/

Or maybe the Header widget area.
https://docs.generatepress.com/article/header-widget/

Thanks, I want same this, but i don't know the name navbar.

👍

No problem. :)