Here is a list of documents that previously (I believe) needed to be sent by mail but due to COVID-19 can now be electronically transmitted to the IRS (https://www.irs.gov/pub/foia/ig/appeals/ap-08-0420-0003.pdf). The list is not inclusive according to the memo. All these memos, do not contain instructions for users but are instructions for IRS employees. I would like to fill in this info.
