File I need to edit is not available in list to copy to child theme.

MultiSite, original theme: Ample
Child Theme is not active.

I’m not WP knowledgeable. I understand the codes, I don’t know them or write them. I just search and destroy – I look that through files until I see what I think is the thing to change/edit.

I need to edit a file called “header-functions.php”.
It is not listed in the files to copy from the parent theme to the generated child theme.

The file contains things for the slider, header image, generated pages like Archives, etc. I want to change the title/header for the Archives page, i.e. change the word “Archives”.

Any direction would be appreciated.
Thank you

https://wordpress.org/plugins/child-theme-configurator/