Microsoft 365 Domains

what are the values for Microsoft default domains? usually we get 2 default domains 

o365.testorg,.com and testorg.onmicrosoft.com and your domain testorg.com.

what are the values for TXT, MX and CNAME?

i see 

TXT   something-testorg-onmicrosoft-com._domainkey  value is v=long string.

all groups there on this domain.  

I also see 

and all of these have values. how it should be ?