For a distribution paid to you within the last 60 days, simply deposit the gross amount of the distribution back into a qualified retirement account like an IRA, perhaps the account from which the RMD was distributed. If you do so, when you prepare your 2020 tax return next year using TurboTax you'll indicate that none of the distribution was an RMD (if 2020 TurboTax asks) and that you rolled over all of the distribution.
Contact your financial institution regarding their procedures for accepting a rollover.
Only for distributions made in 2020 that meet the definition of a coronavirus-related distribution paid to an individual:
(I) who is diagnosed with the virus SARS–CoV–2 or with coronavirus disease 2019 (COVID–19) by a test approved by the Centers for Disease Control and Prevention,
(II) whose spouse or dependent (as defined in section 152 of the Internal Revenue Code of 1986) is diagnosed with such virus or disease by such a test, or
(III) who experiences adverse financial consequences as a result of being quarantined, being furloughed or laid off or having work hours reduced due to such virus or disease, being unable to work due to lack of child care due to such virus or disease, closing or reducing hours of a business owned or operated by the individual due to such virus or disease, or other factors as determined by the Secretary of the Treasury (or the Secretary's delegate).
I just rolled back my RMD, and the withheld taxes are with the IRS. I hope Turbotax makes a special note of this next year for Turbotax 2020 just to make it easier, like, "Did you Rollover your 2020 RMD because of the CARES act?"
Hopefully 2020 TurboTax will eliminate the question asking if any amount of the distribution was RMD and just proceed to asking what you did with the money. (In this case, you moved it to another retirement account and roll over the entire amount.) If TurboTax does ask how much was RMD, the answer is None.
The 60-day rollover limit still still technically applies, but the CARES Act creates the legal fiction that a coronavirus-related distribution (CRD) that is rolled over within 3 years is considered to have been rolled over by the 60th day following the date of the distribution. It's up to the receiving financial institution to accept that the rollover of a CRD.