Hi @Winson_Joseph and welcome.
There are many ways to backup your Magento Database:
- In the backend select System > Backups
- From the Command Line Interface run the following command from the Magento root directory as the magento user:
bin/magento setup:backup --db
- From the Command Line Interface using the
mysqldump
feature (reference)
I wouldn’t do it via phpMyAdmin though. Large Databases normally result in phpMyAdmin timing out. Option 1 or 2 would normally be my goto.