If you haven't redeemed your product key for Office setup for Mac, you'll want to do that before trying to activate. Follow these steps:
Step 1: Go to https://setup--office.com/
Step 2: Sign in with your Microsoft account, or create one if you don't have one (you can create one with any existing email address you already have). Be sure to remember this account so that you can install or reinstall Office later, without a product key.
Step 3: Enter your Office product key, without hyphens.
Step 4: Follow the prompts to finish the redemption process.
OFFICE SETUP | office.com/setup
Where do i enter my office.com/setup key?
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