Good communication skills are essential in this role.
mandatory
Frequency:
70
%
Attendance is mandatory for all employees.
compulsory
Frequency:
60
%
Wearing a helmet is compulsory while riding a bike.
obligatory
Frequency:
50
%
It is obligatory to submit the report by the deadline.
Idiomatic Expressions for required
Phrase: by the book
Meaning: following the rules or guidelines exactly
Usage: We need to handle this project by the book. All required procedures must be followed.