Workplace and job have similar meanings but slightly different meanings.
A workplace is a place where you work for a specific company or organization. In other words, the place or organization where you work. For example, in "I work for Company ABC," "ABC Company" is the place where the person works.
On the other hand, occupation refers to the work or duties performed by an individual. In other words, it means the kind or field of work or work to be performed. For example, in the statement "I am an accountant", "accountant" is the individual's occupation, and it is not specified where this individual works.
Thus, workplace refers to a place or organization in which one works, and occupation refers to the work or task performed by an individual.