Add Local Endpoints
You can only add a local endpoint during the creation of the Portainer container. You cannot add a local endpoint after Portainer was deployed.
You can view how to install Portainer (including adding a local endpoint) in the following articles:
Deploy Portainer in Linux
To learn more go to Deploy Portainer in Linux Environments.
Deploy Portainer in Windows 10 and Windows Server
Adding a local endpoint must be done in the initial setup. To learn more see initial setup