Inside your Business Central, you will have the Advanced Portal Designer app installed. The app receives requests from the website through the Endpoint.

When a request comes into Business Central, it goes through the security parts of Advanced Portal Designer before it is allowed to interact with anything in your system. After the request has passed the security screening, APD will process it.

A request can be these different types of actions:

File	Returning text-based content, typically HTML, Javascript or CSS Stylesheet. But can be any text-based type of file.
Codeunit	Executing a APD-aware codeunit. From this codeunit you can call any piece of business logic in Business Central. Suitable for posting, releasing and other operations like that.
Report	Run a specific report and return the result in PDF or any of the other possible output formats of a Business Central report.
Blob	Returns the content of a blob/Image/Media field in Business Central. One example: This can be used to return the image from the item table.
Data	The data action enables you to interact with data from Business Central as a json web service. You can both get data and update data.
Script	Runs an AL script. Useful for smaller pieces of business logic that doesn’t require a full codeunit.

Apart from the above, you have the following administration options:

Setup	Defining the global
User Management	Manage your portal users and their permissions.
Auth0 Support	You can use Auth0 for authentication
Security Profiles	Manage security profiles that can be assigned to users
Security Settings	Manage security settings for tables in Business Central.
Invitation Codes	Invitation codes can be used to assign users
Template Wizards	Define AI templates to help with designing File Templates