It has several modes. I assume you mean extend a wifi network. They call it "repeater". Their guide is pretty good.

The GL-MT3000 / Beryl AX - GL.iNet is a great little device. I use it with my hotspot. You can use it for many other things as well. It supports Mullvad out of the box and is easy to set up with other VPN providers. It has built in Adguard and much more. I should be getting a commission at this point.

Another use is to connect it to the wired internet at a hotel if they have that. Then use the router (over VPN) on all your other devices. This offers some protection from the hotel wifi and you only pay for one device. If they don't have wired Internet you can connect it to the hotel wifi and share it with your other devices.

I recommend setting this all up at home to get the hang of it. Test everything out before you go on a trip. There are many videos on their travel routers. Most of them have the same software so they pretty much all work the same way. I've had a couple of these things. Given some away.