If the RMD from the IRA that was transferred to you in 2018 was not taken, you are subject to a 50% penalty. You are able to ask for the penalty to be waived. The penalty can be waived due to a reasonable error . Explain the reason that it was missed and add the fact that you have remedied this by taking out the RMD. Include a copy showing that the 2018 RMD was withdrawn along with your explanation of why the RMD was not taken.
The Form 5329 from 2018 must be used. Follow the instructions for Lines 52,53 and 54 to request that the penalty be waived.