Step 1: Install & run Google Mail Backup Tool.
Step 2: Login with Gmail credentials and allow the access to your account.
Step 3: Choose PST/EML/MSG/MBOX file format and apply date or email based filters.
Step 4: After that, select the destination location to save the output file.
Step 5: The process will start and the software will show the report of the backup process.
Step 6: After completion of the process, navigate to the location where you have saved the output file to get the backup.