Step 1: Log in to your Charge Automation account then go to Settings > Preferences > PMS Modification.

Step 2: Turn on 'NEW BOOKING RECEIVED' and save.

Step 3: In your BookingAutomation account, you can use:

Create an Auto Action and put this Template Variable:

https://app.chargeautomation.com/onlinecheckin?bookingid=[BOOKID]&firstname=[GUESTFIRSTNAME] to the email content.

NOTE: Only new bookings received after turning ON "NEW BOOKING RECEIVED" will see the pre check-in link.