Sign in to Microsoft 365 Apps (Microsoft Office) You are here: Main Software Guides Sign in to Microsoft 365 Apps (Microsoft Office) ◄ Knowledge Base Homepage Overview Sign in to Microsoft 365 Apps (Microsoft Office) to activate your license. Sign in These instructions apply to Mac and Windows computers.Open Microsoft Office:* Open the Word, Excel, or PowerPoint app.* Click Sign in or create account.Sign in to Microsoft Office:* Sign in with your @siu.edu email address and password.