Managed account not authorized and want it turned off.

An educated guess at this point. On your iPhone......

Tap Settings

Tap Wi-Fi

Tap Edit in the upper right corner

Scroll down to the bottom of the list to see if there is a listing under Managed Networks

If there is, this "network" was installed by your carrier, so you can access free Wi-Fi at various locations when you are out and about. This has nothing to do with controlling or managing your phone, it is simply a service provided by your carrier.

If you are using AT&T, the name of network might be "AT&T Wi-Fi Passport" or "attwifi"

Note that it is common for carriers to install profiles to let your phone use Wi-Fi hotspots that they own, or to which they have access, to offload data traffic from their cellular networks. You may not be able to opt out of these for as long as you are their customer.

Where are you seeing that it is managed? Post a screenshot if you wish as long as it does not contain any personal information.

What settings are you looking at on the phone that make you think that the phone is managed?

Wi-Fi? If yes, what is the name of the "managed network?"

Something else? If yes, please provide as much information as you can

Screenshots really help

If you are referring to the Managed Wifi networks like suggested by Servant of Cats, that has nothing to do with your Apple Account being managed or even your device being managed. I don't know of any Cellular Provider that does not have at least 1 managed wifi network. If you have T-Mobile, you will see 2 and one is called TmobileWingman that allows free WiFi access on airlines such as Alaska Air.

Without any more information, all we can do is guess what you are referring to.