To digitally sign an Office document, you must have a current (not expired) digital certificate. Digital certificates are typically issued by a certificate authority (CA), which is a trusted third-party entity that issues digital certificates for use by other parties.

To use Microsoft 365 on your new device, you can activate Microsoft 365 as a 1-month trial of Microsoft 365 Family. You can also buy Microsoft 365 or a non-subscription version of Office, add Microsoft 365 to an existing Microsoft 365 subscription, or enter a product key from a new product key card.

You'll find the product code in the property table of the MSI file. The troubleshooter helps fix problems that: Corrupt registry keys on 64-bit operating systems. Corrupt registry keys that control the update data. Prevent new programs from being installed. Prevent existing programs from being completely uninstalled or updated.

Digital signatures support this change by providing assurances about the validity and authenticity of a digital document. For more information, see Add or remove a digital signature in Office files. What do you want to do? What is a digital signature?

To learn about digital signatures (also known as digital ID), what they can be used for, and how to them in Word, Excel, and PowerPoint, see All about digital signatures. In the document or worksheet, place your pointer where you want to create a signature line. On the Insert tab, select Signature Line in the Text group.

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.

Before you begin, make sure your PC or Mac meets the system requirements. If you already redeemed a product key, you're simply reinstalling the apps, or you know you have an assigned license through work or school, you can skip ahead and go to the section sign in to download and install Microsoft 365 or Office.

From the Overview page, select Office apps and on that page, find the Microsoft 365 product you want to install and select Install. To install Microsoft 365 in a different language, or to install the 64-bit version, use the dropdown to find more options. Choose the language and bit version you want, and then select Install.

You can start a scan for malware any time you like. Note: Microsoft Defender currently offers anti-malware on Windows, Android, and macOS. If you want a deeper scan, instead of selecting Quick scan in step 3, select Scan options and choose the type of scan you want. For the most complete scan, run Microsoft Defender Offline.

How to get a digital ID or digital certificate for Outlook to prove your identity and prevent message tampering. Sign your emails with a digital ID.