firstly you purchased Microsoft Office setup come with an activation code? If yes, then you need to input this unique product key by visiting office.com/setup. If you have Microsoft Office 365, then you can also renew your subscription. Launch the internet browser. Enter www.office.com/setup in the URL bar. Log in using your Office account details. Otherwise, make a fresh account in case you are a brand-new user. Make sure to remember the login information or else you will face issues while installing or reinstalling Microsoft Office. You need to type the Office product key in the given space. Follow the prompts shown on display to setup Office completely.