There are a few ways to move emails from one account to another, depending on the email service you're using. Here are some common methods:
Using Gmail:
Enable IMAP: Go to your Gmail settings, click on the "Forwarding and POP/IMAP" tab, and enable IMAP for all mail.
Add Both Accounts to an Email Client: Use an email client like Thunderbird or Outlook. Add both your old and new Gmail accounts.
Drag and Drop Emails: Drag the emails from your old account to the new account's folder in the email client.
Using Outlook:
Export Emails: Open the source account in Outlook, select the emails you want to move, and export them as a PST file.
Import Emails: Open the destination account in Outlook and import the PST file.
Using a Chrome Extension:
Multi Email Forward: Install the Multi Email Forward extension.
Select and Forward: Select all emails in your inbox, click the Multi Email Forward button, and enter the new email address.