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
To learn more go to Deploying on Windows 10 or Deploying on Windows Server.
Initial Setup
Adding a local endpoint must be done in the initial setup. To learn more see initial setup