Export All People in Your Account
The best way to export all people in your account is to create an all-inclusive segment. This segment should include the following condition: Properties about someone > Email contains @.
NoteYou should never email this all-inclusive segment, since it will contain people who have not opted in to receive emails from you. Emailing this segment of people could put your open rates and deliverability at risk.
This will create a segment of all contacts in your account.
Export to CSV
Once this segment is populated, you can export the segment to CSV through the Manage Segment drop-down. The export will contain all people in your account at the time of export.