Do you mean the email that is created and sent when a new mail account is created?
This is done by modifying the following file:
Mail/ClientConfig.*.tmpl
Send the mail client configuration file to a new mail user. This notification template uses the clientconf_manual_settings_include.html.tt sub-template from the Mail/includes directory.
Is it possible for the edit location page to be divided into two or more pages? Because with a lot of text to translate, the page is slow and crashes at times.
Currently there isn't a way to split that up. If you'd like to see that behavior changed it would be a good idea to submit a feature request using the link in my signature below.