How do i use microsoft365 setup product key: complete guide 2026

Setting up Microsoft 365 with a product key ensures full access to Office apps. This guide shows how to locate, enter, install, and activate your key quickly and securely in 2026.

Locate Your Product Key:

• Found in your purchase confirmation email, physical card, or retailer account.
• It is a 25-character alphanumeric code (XXXXX-XXXXX-XXXXX-XXXXX-XXXXX).

Go to Official Setup Page:

• Open https://www.office.com/setup.
• Always use the official Microsoft website to avoid fake activations.

Sign in or Create Microsoft Account:

• Sign in with your existing Microsoft account, or create a new one.
• Linking your product key to your account ensures future access and reinstall options.

Enter Product Key:

• Input the 25-character key in the provided field.
• Double-check for typos to avoid errors.

Select Region and Language:

• Choose your country/region and preferred language.
• This affects updates, support, and default app settings.

Download Microsoft 365 Installer:

• Click Install Office → Office apps.
• A setup file will download to your computer.

Run the Installer:

• Double-click the setup file and follow on-screen instructions.
• Wait for installation to complete; internet connection is required.

Activate Microsoft 365:

• Open any Office app (Word, Excel, PowerPoint).
• Sign in with your Microsoft account; your product key will automatically activate.

Verify Activation:

• Check File → Account → Product Activated to confirm.

Tips & Troubleshooting:

• Keep your Microsoft account login secure.
• Use Microsoft Support if the key shows as invalid or already used.
• You can reinstall Office anytime using the same product key linked to your account.