If you're currently using e-mail for work or business, you're most likely using an Exchange or IMAP account. Microsoft Outlook. Exchange and IMAP servers automatically archive your emails so you can access them anytime or anywhere.
Here's how to back up email in Microsoft Outlook as quoted from the official page Microsoft:
1. Select File then click Open & Export then select the Import or Export option.
2. Select Export to a file and click Next.
3. Select Outlook Data File (.pst) and click Next.
4. Select the email folder you want to backup and click Next.
5. Choose a location and name for your backup file and click Finish.
Now that you have a .pst file, you should be able to import the data in it back into Microsoft Outlook. Here's how:
1. Open the Microsoft Outlook application on your computer or PC.
2. Click File then select Open & Export then select Import/Export.
3. Next, select Import From Another Program or File and then click Next.
4. Select Outlook Data File and click Next.
5. Select the PST file you want to import and choose whether to replace duplicate emails, create duplicate emails, or not import duplicate emails at all. When you're done, click Next.
Your email will now be imported into Microsoft Outlook. If you are importing emails from another account, and you are using IMAP or MAPI, the imported messages will be synchronized with the mail server and you will be able to access them from another device.
Remember that meta data such as folder properties (view, permissions, and Auto Archive settings), message rules, and blocked sender lists are not exported to .pst, so they will also not be imported and you will have to recreate them.