I wanted to use e discovery to get all emails in users mailbox without using the keyword option because I need all the emails, how is this possible

The other question is that does the e discovery only search the Inbox and Sent Items folder ? Or does it search all the folders in the mailbox. Exchange 2010

E Discovery will do search in all folders including dumpster, Also if you are not using keyword then just export the content to pst file and import it to target mailbox.

Please let me know if you have any specific requirement.

Thanks for the quick reply