If the Salesforce Contact or Lead objects have been set for field mapping, then there will also be the option for automatically adding a new Contact or Lead to an active Salesforce Campaign.
For a campaign to appear in the list, it must be set to Active in Salesforce. The Campaign selector will not be displayed if any other objects are selected for mapping.
Next Step
Upload Files to Salesforce as Attachments (Pre-Sitecore 9)