Booking Redirect is a feature enabling customers to find and book services directly from a business’s GMB listing. When a business enables this functionality, it allows potential customers to book appointments or services straight from the Google search results page or the business's Google Maps listing.
You must have a Google Business Profile for this feature.
This feature is designed for businesses based in the United States.
This feature is available for the business below:
Set up a Service Menu or a Group of Services. This should provide a detailed view to help customers easily choose services.
Note: You can learn more about this by reading the article called, “How to Create a Service Calendar”. 
Add the link that allows customers to directly book services. This link should be active and user-friendly. It will be added to the 'Book Online' button on your GMB listing.
Note: To add the booking link, sign into your Google Business Profile, select ‘Booking’, scroll to ‘Add a link’, paste your Booking Page link, and click Save.Individual Service Booking
Use any calendar you have created, which will show up under the services tab on Google.
Select specific calendars (services) in the Individual Service Booking dropdown if you want them to be displayed on Google.
Make sure that the calendars you select have clear descriptions that match the name of the Calendar/Service. This is important for validation on Google's end.
Note: It usually takes 1-2 weeks for the feeds and profiles to be verified for the first time.Tips for Success:
Clear Descriptions: Ensure your services and calendars have clear, concise descriptions that accurately reflect their names.
Link Accuracy: Be meticulous in selecting only the appropriate service menu or group in the Primary Action Feed and the individual calendars' Service Links.
Regular Updates: Keep your service offerings and descriptions up to date to maintain accuracy and relevancy.