The Wix Bookings app will provide a much cleaner and seamless user experience and will be easier to maintain and manage.
If you want or need to use the service you asked about in your post, adding code to an HTML component is not a part of the Corvid product (which is what this forum is about). The basics of an HTML component is to put any HTML code in it. That code can be copied from any source that you want, but you need to know the exact code to put there (which is not related to Corvid )… You will need to check with the service provider to find out how to get it work.