Occupation means an activity in which a person is involved to earn money for his/her livelihood. Occupation might be a job, business or something which doesn’t need any specific skills. The skills required are generalistic in nature.
Example: clerk, shopkeeper, driver etc.
Whereas profession is an activity that wants special skills and training. Even certifications in skills are necessary for the professions. The primary purpose of the profession is to deliver services to those who needed them. And those who are engaged in a profession are called professionals. Moreover, professionals are governed by a statutory body and code of conduct.
Example: Doctors, Lawyers, Chartered Accountant etc.
However, the profession also comes under occupation, which is a broad category since they also earn money for survival. But the difference lies in the skills needed, services rendered, and certifications required.