Due to the pandemic and limited staffing the IRS has not processed any paper tax returns for several months. They have only just recently started to process those tax returns in the order received.
Go to this IRS website for information - https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue
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.
Do not file a second tax return or contact the IRS about the status of your return.
Go to this IRS website for the status of a federal amended tax return, Form 1040X, that you mailed to the IRS - https://www.irs.gov/filing/wheres-my-amended-return