The only emails that get sent to guests automatically are confirmation of payment received emails when the deposit and balances have been paid by the guest if they pay online via the booking link set up by the website owner.
However, please note that this is slightly different if you're using the Book Now Widget also.
If you've set the system to allow instant booking, guests will automatically receive a payment confirmation email once they've completed the booking process.
If you've set the system to not allow instant booking, guests will automatically receive the 'booking request received' email i.e. Provisional/Unconfirmed.
The system will send email reminders to you when guest emails are due to go out.
For example when it is time to chase the next payment. But in order for these to be sent, you will need to log into your reservation manager and send them manually.
The system does not automate guest emails for the simple reason of avoiding any emails going out accidentally due to an incorrect status change (as an example).
If you have overridden the default templates for the deposit received and balance received emails, the system will send your template, instead of the default.