Change Password Mail

Hi,
do you mean the message that is sent when a user checks the “Create account …” checkbox in the [adverts_add] form or the default password change sent by WP?

In both cases, you can set the From header using a third-party plugin like https://ww.wp.xz.cn/plugins/cb-change-mail-sender/

As for the message body:

– if you want to customize the message when a user submits an Ad and registers you can use the Custom Registration Email snippet https://github.com/simpliko/wpadverts-snippets/blob/master/custom-registration-email/custom-registration-email.php

How to use it you can read here https://github.com/simpliko/wpadverts-snippets/ at the bottom of the page.

– if you want to change the default WP password change email template then you would need to follow the explanation here https://wordpress.stackexchange.com/questions/321025/how-can-i-modify-the-default-reset-lost-password-email-text