Seamless is built on top of SharePoint Online from Microsoft 365/Office 365 and therefore requires an active SharePoint Online subscription. Each person who accesses SharePoint Online must be assigned to an Office 365 plan (E1-E5, K1). SharePoint Online Plan 1 or SharePoint Online Plan 2 standalone service can also be used.
External Seamless users requires an Office 365 Work or School Account or a Microsoft Personal Account (Live-ID) for sign in. Sign-up for a new Live-ID for free under signup.live.com.
For the best user experience, we also recommend licensing and installing Office 365 ProPlus on your PC or Mac.