It depends on the settings within your software. There is a setting in Advanced Features
where you can choose to either let them write their own messages, or to not write their own message.
, it can send emails to everyone including suspended members. There is an option where you can select if it should include suspended Members or not (and also an option to email only suspended Members).
When logged in as the admin go to "Autoresponder Emails"
Click "Edit Create New Account Email"
On that page you can edit the content of the email sent after a member creates an account at yoursite.com/join