People who need to see or work with your SharePoint Online site content but who don’t have user accounts for your SharePoint Online environment are considered “external users.” External users might be vendors or customers, for example. With SharePoint Online, after you activate the sharing feature, you can invite an external user to your site just by sending them an email with an invitation (the invitation expires after one use).
Just follow the simple three steps in the article "Share a site with external users" to enable the sharing feature and then follow the steps in this article "Grant permissions for a site" to grant and restrict access to your site and content. This is called managing permissions and you do it by using security groups, which control membership, or by using fine-grained permissions, which help you control content at the item or document level.
The Office 365 terminology for external users is Partner Access Licenses (PALs). A PAL
- is free (service plan caps apply, currently 500 for the P plan and 10,000 for the E plan)
- is granted permission by the site admin and can have Read, Contribute, or Owner permission
- When composing an invitation to a PAL you'll have the option of granting the invitee either contributor or viewer - member or visitor - permissions. Once the invitee has accepted the invitation you'll be able to move the invitee to another security group if needed.
- Invitees who hasnt accepted an invitation (yet) do not show up in the list of users since their userid doesnt exist
- that is an Owner have the ability to invite others PALs
- can read documents, but cannot edit them via the Web Apps (editing with own licensed Office rich client is allowed)
- can get site feeds, but do not get a MySite, cannot receive company feeds or follow others
- can be invited using any email address that is registered in the LiveID system
- You can view a list of all users (including the PALs) for a site using the syntax:
- You can check any user's (or group's) permissions using the "Check Permissions" button on the "Permissions Tools" ribbon (Site Actions > Site Settings > Site Permissions)