Instead of purchasing a product key, preactivated versions often include scripts or modified files ( .dll ) that trick the software into thinking it is validly licensed.
A preactivated version of Microsoft Office 2013 is a copy of the software that has already been activated, meaning that the user doesn't need to enter a product key or activate the software manually. This can be a convenient option for users who want to access the software without going through the activation process.
Instead of risking your data and legality, here are legitimate ways to get a full-featured Office suite for free or at a low cost.