Hi @johndos,
Yes, you will need to add the locale code for Greek as el as a suffix to the file name. For example: woocommerce-call-for-price-el.po
Can you please let me know whether you have saved the new .po, .mo files as I have explained in above example?
Also, let me know whether you have placed these saved translated files in Upload the files in the langs folder of woocommerce-call-for-price plugin and in wp-content/languages folders?
Also, you can use free plugins as well to translate the plugin/theme strings and in order to avoid all this steps. For example: Loco translate.
Yes, the changes in the files will not be reflected when cache plugins are used on the site. Everytime the developer or store owner needs to clear the cache in order to reflect the changes on the site.
Regards,
Komal Maru