https://www.home-assistant.io/docs/authentication/providers/
Simple single user example:
Note: I think this is due to my proxy setup, but this allowed remote unauthenticated logins, so I just removed the whole block
homeassistant:
auth_providers:
- type: trusted_networks
trusted_networks:
- 192.168.0.0/24
- 127.0.0.1
- ::1
allow_bypass_login: true
- type: homeassistant