What do I do if on the screen says “remote management “

The presence of a management profile indicates that the device is centrally managed by an Enterprise or Educational establishment. Devices that are configuration locked by an MDM platform can usually only be released from central management by the platform that manages the device. Be aware that Apple will not assist with removal of management profiles.

Unless you are lucky - and have the option to delete the profile from iPad Settings - you’ll need to seek assistance directly from the System Administrator who manages the device. 

Install or remove configuration profiles on iPad - Apple Support

If you want to remove the profile on your iPad, check Settings/ General / VPN & Device Management.

You might have to ask the person or institution, who installed the profile, to remove it.