You report a distribution from 2020 on 8915E which is in the program, but not ready yet. From Q&A IRS:

A13. If you are a qualified individual, you may designate any eligible distribution as a coronavirus-related distribution as long as the total amount that you designate as coronavirus-related distributions is not more than $100,000. As noted earlier, a qualified individual may treat a distribution that meets the requirements to be a coronavirus-related distribution as such a distribution, regardless of whether the eligible retirement plan treats the distribution as a coronavirus-related distribution. A coronavirus-related distribution should be reported on your individual federal income tax return for 2020. You must include the taxable portion of the distribution in income ratably over the 3-year period – 2020, 2021, and 2022 – unless you elect to include the entire amount in income in 2020. Whether or not you are required to file a federal income tax return, you would use Form 8915-E (which is expected to be available before the end of 2020) to report any repayment of a coronavirus-related distribution and to determine the amount of any coronavirus-related distribution includible in income for a year. See generally section 4 of Notice 2005-92.