I found myself looking at Microsoft Booking the other day.
If you are not familiar with Microsoft Bookings, its an simple booking engine designed for small businesses.

Customers can create a booking through a web page specifying the time and service required, receive a confirmation email and calendar invitation, and reschedule or cancel if needs be. As a business owner you can track booking through the application and through Outlook.
You can read more about it here: https://products.office.com/en-za/business/scheduling-and-booking-app
If you have Office 365 Business Premium or an educational subscription (A3 or A5) you probably know about it already, however the main reason for this post was that a lot of enterprise customers may not know about it or that they have it available.
Large enterprise organisation may have some small facilities or services that require booking by the public as we do and this could be the perfect tool.
If you have an E3 or E5 licence you can add the Microsoft Booking app to your subscription by ‘purchasing’ the free license in the O365 admin portal.
In the admin centre, go to Billing > Purchase services and select Business Apps (free), hover your mouse or click anywhere on the card to display the Buy now button, and then click Buy now. It is free (as at date of this post) I promise!

Full instructions can be found here https://support.office.com/en-us/article/get-access-to-microsoft-bookings-5382dc07-aaa5-45c9-8767-502333b214ce as to how to add this tool to your E3 or E5 subscription.
Are you using Microsoft Bookings as a small business or a large enterprise?