I amended my return and submitted it. How do I download original return?

Sorry, unless you downloaded it before you amended, the amended return overwrote the original return and it is gone.  Only the last return done is saved.  

You can request a transcript from the IRS

https://www.irs.gov/individuals/get-transcript

For a fee of $43 you can get a complete federal tax return from the IRS by completing Form 4506

https://www.irs.gov/pub/irs-pdf/f4506.pdf

Thank you for the quick reply and response!

I will certainly remember to download every time I submit.

Thank you!

If you did not save the original return as a pdf--per the instructions--then when you amended the return, the original was replaced by the amended return.  The original is gone.

You can get a free transcript from the IRS or for a fee of $43, an actual copy of your tax return.

https://www.irs.gov/individuals/get-transcript

https://www.irs.gov/pub/irs-pdf/f4506.pdf