Options for migrating mail from Google Accounts or IMAP servers
If you've created a new G Suite account for your organization's email, you can migrate your data from your old Google Account or an IMAP server, using one of the following tools:
Data migration service
The data migration service is the recommended way to migrate mail. It's clientless and cloud-based and easy to set up and monitor. You do everything in the Google Admin console.
Check the data migration service prerequisites before you begin.
G Suite Migration for Microsoft® Exchange (GSMME)
GSMME is a utility that migrates your mail, including labels and archived mail, to your G Suite account. GSMME can also migrate other data, but requires you to install the tool first. For details on how to migrate data using GSMME, see Use GSMME to migrate mail from Google accounts or IMAP servers.
Check the GSMME prerequisites before you begin.
Third party tools
You can also check out the G Suite Marketplace to review migration solutions provided by third parties.