Hi daniel.roostania,
Thanks for reaching to us.
+ In order to change / translate words. Please make sure you synced the strings first before changing / translating WooCommerce, WoodMart Core plugins and WoodMart theme. You can refer to article https://xtemos.com/docs-topic/theme-translation/
+ You are also need to select the language for the backend and theme settings for admin from the admin user profile, please edit the user’s profile and then select the language for that user it will show the same on the backend.
Regards,