Disclaimer: Dependent on your settings, you will be able to share campaigns to another user in your group or client. If you follow these steps and do not see a user on the drop down menu, please contact the Helpdesk.
Firstly, go to reports in the main navigation menu.
Find the campaign you'd like to share, click the drop down menu at the right hand side then click Sharing.
Click 'Share this campaign' where you will be prompted to either share with the entirety of your Client, or with an individual user. (As per the disclaimer, depending on your accounts sharing level you can either send to users in your group, client or partner)
Click Add Share and you will be taken to a screen where you will see all of the users that your campaign has been shared with. From here you can also delete a share by pressing the delete button next to the users name.
To find your shared campaigns, go to Reports, Shared Campaigns and you will find the campaigns that other users have shared with you.
Note: Sharing a template is done in the same way but from the Survey tab. Also, the template used to create the campaign must be in the user that it is being shared to, as shown here.