If you timely filed your 2019 tax return or you requested a filing extension, you have until October 15, 2020 to obtain a return of the excess contribution made for 2019. You can then do whatever you want with that money, including using it to fund a 2020 IRA contribution that you are eligible to make.
You'll receive a 2020 Form 1099-R reporting the return of the 2019 contribution. Any earnings required to accompany that returned contribution will need to be reported on your 2019 tax return, subject to income tax and potential early-distribution penalty, so you'll need to make sure that your 2019 tax return reflects the returned contribution.
If the investment gains attributable to the excess contribution are substantial, say 30% or more, it might be more beneficial to pay the excess-contribution penalty for 2019 and apply the excess as part or all of your 2020 Roth IRA contribution, allowing the gains to remain in the Roth IRA and not be subject to tax or penalty.
If the excess was the result of being over the AGI threshold, you also have the option to recharacterize the Roth IRA contribution to be a traditional IRA contribution instead. This may be beneficial if the Roth IRA has lost value since the time the contribution was made.
