AMA: Enabling cloud-based device management with cloud attach

Here are the prerequisites for co-management: https://docs.microsoft.com/mem/configmgr/comanage/overview#prerequisites 

Not on a technical level, however, co-management is *not* a remote management solution and you will have issues if the ConfigMgr agent cannot communicate with the ConfigMgr site for an extended period of time. Thus, I strongly recommend not doing this if remote management is in scope and you have no other regular connectivity between the managed endpoints and ConfigMgr (like a VPN).