In order for wifi to work, do I have to have a device plugged into it?

WiFi should work for any device if you're logged-in to your gateway. When it stops working in certain areas that's usually due to distance limitation, interference (walls for example) or a weak signal. The 2.4GHz band can usually work around some interferences but doesn't have a long range. The 5GHz band, otoh, has greater distance but is more susceptible to interference.

Just move your computer to where you want it and see if you can connect to your WiFi with speeds and reliability that's acceptable. If not, there are other options for improving WiFi.

If you physically connect a device to your gateway you're using an ethernet connection, which is a wired connection. If you don't want to physically connect your computer to the gateway, then you need to use WiFi and setup your computer accordingly.

So no device has to be hooked into it for it to continue working?

@Spaceag  To get internet to your computer, or any internet-capable device you need to either physically connect the device to your router with an ethernet cable or connect your device wirelessly which would be WiFi. Either connection needs to have the connected device configured for that particular type of connection.

Thank you all!