Migrate Mail Data Here's how to migrate your previous mail that stored in UGM local server to your new Google Apps account.
To get started, follow the steps below. Before you begin, keep in
mind that you'll need to have access to the other email account for this
process to work:
Click the gear icon in the top right-hand corner of your inbox, then select Settings.
Under the Accounts and Import tab, click the Import mail and contacts link.
This will start a setup flow. After you finish, it may take some
time for it to import, but you can check the status of your import by
going back to the the Accounts and Import tab on the Settings page.
Since only email in inbox will be migrated, So if you want to migrate other email from different folder, you can move it to inbox first.
in the top right-hand corner of your inbox, then select Settings.