If you need someone to have the ability to create courses then the best role for this is the Course Creator. Users with this role can also manage courses (enrolling Learners, editing settings etc.).
This role would normally be applied at category level to allow the role holder to add new courses to that category (and any sub-categories).
If you are just getting started as a Course Creator in Totara, you may find the quick-start guide useful.
Find out more about the other default roles in Totara.