How can I put GTM code in the <head> of an order form?

Hi All,

Is there a way to put GTM (Google Tag Manager) code into the head of an order form? I tried to create a new theme but that only allows for the addition of CSS. It does have html sections but those all live in the section of the order form I believe. Any help would be greatly appreciated.


Can ANYONE answer this?!! This should be the most basic thing in the world. Nothing? Come on guys…