Your regulatory ID is your CQC ID, and is a 10-digit number which can be found on your certificate of registration.
You can also find this by heading to the CQC website, finding the page for your home and copying the code in the URL.
This can also be seen as the 'Certificate number'. Once you've found this, head to settings in the Care Office, then click on 'Service Profile' on the left-hand side of your screen and scroll down to the 'Regulator' section.
Click on the pencil icon next to Regulatory Identifier to add your ID, once done, just press the green tick to save.