Does Replo have header elements?

More like this, as to how Instant does it

Unfortunately, we don't support native navigational elements. However, you could hard code them and build it from scratch in our editor. Then use page settings to hide the theme header and footer.

Ok would I have to manually add it to every page?

Yup. You can also save sections so it's easier to reuse/access. https://www.loom.com/share/6f81958bfa7d4a6d96e9c2ae514fc76d?sid=90edc779-11d5-4892-827c-a605688e897b