How to hide the history tab of the work item window in TFS2018?what should i do?
I have tried to configure the work item template through XML, but it cannot take effect.
For some reason, I don't want users to see the history module. If i can't hide the history tab, what better advice would you have?

The History tab is the default system-defined tab.
I am afraid that there is no such method can hide history tab of the work item in XML Process or Inherited Process for the time being.
At the same time, if the users have permission to access/read the Work Item, the user can directly view the Work item's history tab.
There is currently no method/specific permissions to restrict users from accessing Work item history.
Now, we can prevent users from accessing Work items of specific Area Paths by setting permissions in Project Settings -> Team Configuration.
In this case, we can restrict users to only access the work items and history of the team they belong to.
I can fully understand your requirement. You can submit a suggest ticket in the site: Developer Community to report this feature.