On 2020 form 4684, under FEMA code, what are EM or DR?

[qbteachmt]

Are you asking about their Coding Prefix?

https://www.fema.gov/pdf/library/2300_15ch7.pdf

DR = Disaster type:
DR = major disaster declaration
FS = fire suppression assistance
EM = emergency declaration

[qbteachmt]

Did you want the Lookup link:

https://www.fema.gov/disasters/disaster-declarations