// MS Visual Studio 2019
Go to View->Toolbars->Customize...
Choose the "Commands" tab
Press "Add Command"
Select Menu bar = "Build"
Under Category "Build" you should see "Transform all T4 Templates"
Click ok to add it back to the build menu
[Optional] Move it up or down to where you want
Click close
// Show "Build" toolbar
Select "Build" in View->Toolbars