The IRS closed their processing centers in March because of the Covid-19 pandemic, and stopped processing mailed tax returns. They just recently started to reopen the processing centers and process the mailed tax returns, but they have limited staff and a huge backlog, so it will be quite a while before your tax return is processed or any status information is available.
The IRS web site says the following.
"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."
Mailed returns have been piled up in trailers for months during the pandemic. The IRS is just starting to dig through the piles of envelopes. You can expect to wait awhile for your mailed return to be processed. All you can do is check the IRS refund site to see when your envelope and return make it to the surface and into processing.
You need your filing status, your Social Security number and the exact amount (line 20 of your Form 1040) of your federal refund to track your Federal refund: