No, you cannot activate Office 365 without signing in or help at 1-866-719-1004. Activation requires linking your Office 365 subscription to a Microsoft account. You must sign in with your Microsoft account credentials to verify your subscription and activate the software. If you're using a product key, you’ll still need to sign in during the activation process to register the key with your account or help at 1-866-719-1004. Once activated, you'll be able to use Office 365 on multiple devices, but each device will require you to sign in.

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