Microsoft Office 365Your Office anywhere, anytime
If you signed up for the trial via the Office website, visit the Microsoft Account site and turn off auto-renew. With this approach, the trial will automatically expire when your month is finished and your credit card will not be charged.
If you signed up for the trial by clicking an icon on your new PC, your trial ends automatically after a month; it isn’t necessary to cancel it. When the trial ends, you’ll be prompted to choose which version of Office you want to purchase.