How to prevent registered users from changing their data, such as their username, etc. (via edit profile) in the interface?
open components\com_users\models\forms\profile.xml and then edit:
components\com_users\models\forms\profile.xml
<field name="password1" type="password" readonly="true" />
You can enter input fields in the "disabled" attribute and do not want to be changed. Most users will not discuss the source code of the page with you.
<input type="text" disabled="disabled" />