This article explains how to change text in User - Profile plugin fields. You can use the same instructions to override pretty much any text filed in Joomla.
Let's say we want to change Address 1: to Your Address:
First off all find the original text you want to change in Joomla language file.
Language files are located in two places:
In our case for the backend we open file /administrator/language/en-GB/en-GB.plg_user_profile.ini and copy following lines:
PLG_USER_PROFILE_FIELD_ADDRESS1_DESC="Choose an option for the field Address1"
In theory you could simply edit text in here and it would work just fine. Problem with this approach is that any Joomla update may overwrite this file with original values. This is why we should use language override files which are normally not touched by the updates.
Open backed language override file:
paste the copied lines and change text between quotes as required:
PLG_USER_PROFILE_FIELD_ADDRESS1_DESC="Choose an option for the field Your Address"
This will take care of what you see in the backend.
To change text in the frontend open frontend language override file:
paste the same text and edit as required:
PLG_USER_PROFILE_FIELD_ADDRESS1_DESC="Please Enter Your Address"