The IRS does not acknowledge amended returns that can only be mailed.
Amended returns take 8-12 weeks to process (sometimes 16 weeks - that is 4 months).
You can check the status of the amended return here, but allow 3 weeks after mailing.
https://www.irs.gov/filing/individuals/amended-returns-form-1040-x-/wheres-my-amended-return-1
(It is always a good idea to mail using certified mail with a return receipt, or other tracking service, to verify that it was received by the IRS.)
How can I print out my amended IRS return? I got my return $$$ from the State of Calif. which was mailed at the same time.
In normal times it takes up to 16 weeks or more to process an Amended 1040X return. But these are not normal times. They just started opening the mail in June that's been stacking up. Back in March the IRS closed their processing centers and stopped processing mailed tax returns. An IRS spokesperson recently said that they have about 11 million pieces of unopened mail. The IRS says.."We’re experiencing delays in processing paper tax returns due to limited staffing. If you already filed a paper return, we will process it in the order we received it." So you have to keep waiting.
See this IRS page for the latest information
https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue
Then once they start opening the mail, After 3 weeks you can track it here,
https://www.irs.gov/filing/individuals/amended-returns-form-1040-x-/wheres-my-amended-return-1