An amended tax return can only be filed by mail. The following TurboTax provides directions on how to amend your return: https://turbotax.intuit.com/tax-tips/amend-return/how-to-file-an-amended-return-with-the-irs/L6kO691...
Once you have filed, here's how to track your amended return: https://www.irs.gov/filing/wheres-my-amended-return