Pretty frequently I am creating .htm and .tis files. For example for testing purposes.
Usually such files use common template like html/head/body elements, etc.

Here is the add-html-template.reg file that adds “New HTML Document” into context menu of Windows Explorer. So to create HTML file it is enough to right-click in some folder and select “New/New HTML Document” menu item.

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\.htm\ShellNew]
"FileName"="C:\\utils\\template.htm"

Copy block of text above into, say, file named add-html-template.reg and double-click on it to run. Registry Editor will ask permission to update registry. “Ok” on that and reboot Windows (or restart Windows Explorer). Done.

Last note: path after “FileName” – it should contain real path of the template.