Explanation
Campaign members are created from lead, contact, or person account records. Salesforce provides a variety of ways in which you can manage your campaign members. You can add and update up to 50,000 campaign members at a time through lead, contact, and person account reports; you can search for and add or edit multiple leads and contacts from the Manage Members page; you can add an unlimited number of leads and contacts using a CSV import file; or you can add members to a campaign one at a time from contact or lead detail pages.