When you look at Sign In’s for Azure AD it defaults to showing you user sign ins.

MSISignIns_*.csv

ApplicationSignIns_*.csv

CSV Columns

Date (UTC), Request ID, Correlation ID, Service principal ID, Service principal name ,Credential key ID ,Credential thumbprint, Application Application ID,  Resource Resource ID,  Resource tenant ID, Home tenant ID, Home tenant name, IP address, Location, Status, Sign-in, error code, Failure, reason Conditional Access