I want to setup Hyper-V VMs with a shared vhdx or vhds virtual disk. I have a W10 VM that has the main file space and setup a shared folder to allow two other W10 VMs to map a drive and share the data. I suspect performance may be better is I use a shared VHD in Hyper-V. The host computer is Server 2016 Std. I can create the shared VHD but when I try to attach it to a VM, I get an error that says the VHDX location doesn't support sharing. I found several articles saying I need to enable it but I cannot find where to enable it. I have two 2016 servers in a datacenter and several VMs on each but no clustering is setup.
SnapOverflow
As mentioned, you can't use shared VHDX in W10 VMs simultaneously. The best way would be deploying a File Share, which will be accessed from your VMs. Since you have 2 nodes, you can deploy Failover Cluster with either S2D or StarWind VSAN and then configure HA File Share on top (in case you need high availability). The following guide covers the configuration: https://www.starwindsoftware.com/resource-library/starwind-virtual-san-for-hyper-v-2-node-hyperconverged-scenario-with-windows-server-2016/
Sharing a file system not intended for active/active cluster usage between multiple machines will cause problems if you ever get it to work.
A file share is the correct solution for your use case. If you need higher performance, install a higher-bandwidth network and secondarily switch to faster storage.