How can i get connect an external user to Gitlab Self-Manage?

Hi, i have this issue. An external user need to connect to Gitlab Self-Managed, how can i do that? This user is not of the company, when a user of my company is in smart working and need to connect to Gitlab use VPN. How can i do that? With a domain?
Thanks to everyone

Well, if access is only via VPN, then you need to give this user a VPN. Otherwise, you need to open access to your Gitlab install via the firewall for HTTP/HTTPS plus maybe SSH also if you want commits via SSH. You will also need the external_url to be a resolvable hostname and domain name purchased so that it can be accessible publicly. With the domain, you will need to reconfigure gitlab, once the domain is configured and pointed to your server.

Even if via VPN or public access, you need to create a user account for that person so that they can login. Unless you have registration enabled in your configuration as they can then register themselves once VPN access or public access is allowed.