I have several devices but only one shows “Hidden Network”for the wi-fi network that all the devices use. How do I resolve this.

Which device shows "hidden network"?

If you are using a hidden network......not sure if you were aware that a "hidden network" is not really hidden. The name of the network is always being transmitted. Otherwise, devices would not be able to connect.

There are free tools available on the Internet that will display a "hidden" network in seconds, so it won't offer any more protection than a normal network if the bad guys in the van across the street are trying to hack in.

For what it's worth, Apple does not recommend that you use a hidden network for the same reason, plus a hidden network can sometimes make it more difficult for some devices to connect, even when they know the name of the network and password. More details here:

Recommended settings for Wi-Fi routers and access pointsOfficial Apple Support › en-us