Hi,
what’s the best configuration for a vm or hardware size.
the users will be log on via rdp to epicor client.
There is the Hardware Sizing guide from Epicor that can be found on EpicWeb as part of the documentation collateral for the version you will be installing. There are a lot of things to consider (like RDP) which will affect the answer as there is no easy one-size-fits-all answer to your question.
And you will need to take the Epicor recommendations and add to that the Microsoft minimum requirements for your user count in RDP.
You should also consider the HTML client which will (in my opinion) eliminate the need for RDP. Should you implement that instead RDP and the additional license costs for RDP users?