Altium Designer Parameter Set
In your schematic template file, add parameters to the sheet, like so:



Where SCH_TITLE here actually says "=SCH_TITLE" inside the property.  For Engineer, it's "=Engineer" (without the quotes).  And so on.

Then under Design -> Document Options -> Parameters, simply fill out the values you want to populate with each instantiation of each template. 



These aren't magic reserved strings, they can be whatever you want.  But they need to match where they are defined. Certain ones are defined in the actual PCB Project.  For example, for my schematic Part Number, I've got =SCH_PN.  Then in the actual project, in the schematic view, click Project -> Project Options -> Parameters.  Here you can define them.  



Note that some of these are for the PCB versus the Sch.  I use them to populate the part number and PCB title in silkscreen on the board.  For that, it's the same idea, but there you use a period to indicate to Altium that this is a keyword.  So in silkscreen I place ".PCB_TITLE" (no quotes) and it will populate it.  Without the . it would literally put "PCB_TITLE" on your board.

Hope that helps.