You may need a selection file to send to an external partner that does not have a connecter to the Master Intelligence Platform. In that case, it is best to choose to export your file to SFTP.
The name of the file on SFTP will be the same as the name of the action in MIP. Make sure the name of the action is clear and recognizable.
Keep in mind that the selection and subsequent sync may take some time. Always schedule the start of execution (scheduling) a little earlier than the time you need the selection on SFTP.