To change from a 32-bit version to a 64-bit version or vice versa, you need to uninstall Microsoft 365 first (including any stand-alone Microsoft 365 apps you have such as Project of Visio). Once the uninstall is complete, sign in again to m365.cloud.microsoft/apps and select Install apps.

Be sure you're connected to the Internet and then open any application, such as Word or Excel. In most cases, the Office or Microsoft 365 apps are activated once you start an application and after you click Accept to agree to the Microsoft Software License terms.

Download and install or reinstall Office 2021, Office 2019, or Office 2016. Important: Support for Office 2016 and Office 2019 ended on October 14, 2025 and there will be no extension and no extended security updates. All of your Office 2016 and Office 2019 apps will continue to function.

Go to m365.cloud.microsoft/apps and sign in with your Microsoft 365 account. Select Install and more, and then select Install Microsoft 365 apps. Select Install Office, and then open the OfficeSetup.exe file that downloads to your computer.

When asked, Do you want to allow this app to make changes to your device?, choose Yes. When installation is complete, you can take the tour if you like. Then close the tour and the installation dialog box. Was this information helpful?

Open the Office folder in the virtual drive, and then select either the Setup32.exe to install the 32-bit version of Microsoft 365, or Setup64.exe to install the 64-bit version to begin the offline installation. If you're not sure which version is right for you, see Choose the 64-bit or 32-bit version of Office.

Step 1: Go to www.office.com/setup or Microsoft365.com/setup. Step 2: Sign in with your Microsoft account, or create one if you don't have one. Be sure to remember this account so that you can install or reinstall Office later, without a product key.

If you're looking for the steps to download and install the latest version of Office such as Microsoft 365, Office 2021, Office 2019, or Office 2016, see Install Office on your PC or Mac. How do I reinstall Office? If you're reinstalling Office on a different computer than the one where you originally installed Office, note the following:

Insert the Office 2010 disc into the drive. If the setup wizard doesn't start automatically, navigate to the disc drive and click SETUP.EXE. When prompted, enter the product key. If you need help, see Find your product key for Office 2010. Read and accept the Microsoft Software License Terms, and then click Continue.

Learn how to activate Office that is pre-installed on new Windows 10 PCs or using a new product key.