Yes, you can convert the trial version to the full version of Office for Mac.
Step 1
To convert your product you will need a valid product key. There are two ways to obtain a vailid product key.
Option 1: Purchase a product key online.
Open any Office for Mac application. On the first screen of the Microsoft Office Setup Assistant, click
Purchase a product key online. After you have completed your online purchase your Office for Mac product key will be emailed to you.

Figure 2 - Expired trial options
Option 2: Purchase traditional boxed software at retail store.
Purchase a physical box of Office for Mac online or at a retail store. Inside the package, you will find your product key.
Step 2
After you have purchased your product key, open any Office for Mac application to get to the Office Setup Assistant. Click Enter your product key and complete the instructions on the following screens.