lukeG-7

Problem:
I translate the page and save the translation, but when I go to a page for that language i.e. http://example.com/en/about-us/ the content of the header is still the default.

Solution:
First of all, please go to WPML → Settings → Custom XML Configuration tab and add this XML config to it:

Once you did this, please edit the header template:
https://website.com/wp-admin/post.php?post=16&action=edit&lang=en

Now, use the top admin language switcher and select Spanish:
https://website.com/wp-admin/post.php?post=22&action=edit&lang=es

Here, edit the Permalink and change fmt-header to fmt-header-es (just simply add -es at the end, so the permalink in each language can be different).

The last step is to go to WPML → String Translation and search for the header template permalink. In the test website is fmt-header. As the translation, just simply add the permalink that you just set, fmt-header-es.

This time, when checking a page in the secondary language, the translated header will be used:
https://website.com/es/

Relevant Documentation:
https://wpml.org/documentation/getting-started-guide/string-translation/finding-strings-that-dont-appear-on-the-string-translation-page/#strings-arent-selected-for-translation