Hi efpe,

Changing strings of the theme can be done through a translation plugin, it will scan the words and you can change that easily without needing to edit theme files.

To translate or rename theme strings, you can do this via Loco Translate plugin. If you don't have it, please install and activate the plugin in your WordPress site.

1. Then go to Loco Translate > Manage Translations
2. Click "New Language" for the current active theme (if you didn't created it yet, otherwise ignore this step). On the new language page, choose these options – Screenshot
3. After that you will be redirected to the editing screen for theme translations. Before you continue with your translations make sure the current language of your site is selected – Screenshot
4. Follow these instructions to learn how to translate strings – Screenshot
5. The changes will be applied immediately – Screenshot

Note: Translation files will be saved to wp-content/themes/{theme-name}/languages folder or global directory of theme translations: wp-content/languages/themes/ (based on your choice). 

If you have saved your translations inside theme folder, always save a backup of languages/ folder (inside the theme) when there is new theme update. After you update the theme (languages folder will be replaced with an empty folder), just move the backup files you previously saved to the same languages directory and your changes will still be applied.

Hi efpe,

Sorry I have misunderstood you then, unfortunately adding new badges is not possible so what you can do as a partially fix is use the "featured" badge if you don't usually mark items as featured, and so on you can change the Featured word to Sold Out.