Microsoft 365 Download for Mac Free Sign in to download Role Go to world wide web.part.com and if you're not already signed in, select Sign in . Sign in with the business relationship you associated with this version of Part. This business relationship can be a Microsoft account, or work or school business relationship. I forgot the business relationship I apply with Office Subsequently signing in, follow the steps that match the type of account you signed in with. You signed in with a Microsoft account From the Office home page select