From the Admin console Home page, go to Data migration.
To see Data migration, you might have to click More controls at the bottom.
Select the Email option and click Continue.
On the Email Migration screen:
From the Migration source list, select IMAP server
From the Connection protocol list, select IMAP protocol and enter the IMAP details of server ( eg :imap.mail.yahoo.com:993)
Enter the role account information for your yahoo account.
Click Connect. The data migration service attempts to detect your old G Suite account.
(Optional) If the detection fails:
Verify the connection protocol and role account information is correct.
Click Connect again.
In the Migration start date and Migration options sections,select your start date and click Next.
Click Select Users.
Point to Add + and click Select user .
In the Migrate From field, enter the user's IMAP Email address and password.
In the Migrate To field, start typing the user's new G Suite email address and choose from the list of suggested users.
(Optional) To migrate another user's email, repeat the steps.
Tip: To exit a completed migration, click Settings > Exit migration.