Moodle has a Panjabi language pack already. You can add this to your site in Site administration > Language > Language packs. You will see Panjabi if you scroll down the list of available languages on the right hand side. It is right after Oriya. Panjabi has language code pan.
For more on adding languages and how to adjust settings for users to they can use it, see here: https://docs.moodle.org/32/en/Language
Adding a language pack will allow you to change the Moodle interface from default English to Panjabi. It does not affect any content you add, which will be in whatever language it has.
If you find any issues with the language pack, such as typos, mistranslations, or missing translations, then you can follow the link that Helen gave in here post above to the language maintainer area and help improve it.