Zotero allows you to share a library of resources with any number of people in a ‘Group’. The process differs slightly according to whether you are using the online or desktop version of Zotero.

Zotero - online version

1. Click Groups

2. Select Create a New Group
3. Name your Group, and choose a group type (you can change these settings at any time):

• Public, Open Membership - Anyone can view your group online and join the group instantly.
• Public, Closed Membership - Anyone can view your group online, but members must apply or be invited.
• Private Membership - Only members can view your group online and must be invited to join.

4. In the online version of Zotero you will now see your new group listed in the Groups tab. If you are using the desktop version you need an additional step. To add people, click on Manage Members: 

5. On the next page click Send More invitations. Type members emails into the box:
6. Name your Group, and choose a group type (you can change these settings at any time):

You can change member roles at any time in Members Settings:

Zotero - desktop version

1. Follow the instructions above up to step 4. 
2. At step 4, to see your new group listed in your library you need to click on the small green refresh button in the top right:

Your new group will then be listed in your library:

Collaborate on PDFs

It's also possible to annotate PDFs in your Group library and see fellow collaborators' comments.