Similar words with and the difference in Business Communication

What to know about Business Communication?

Employee: A person who works for a company.
Employer: The person or the company who gives the jobs.

Salary: Fixed money you get from your job every month.
Income: All money you get and other sources (salary, freelance work, and others).

Cost: The total amount a business spends to make or get a product.  Price: The amount the customer pays to buy the product.

Invoice: A bill sent by a seller to request payment with the payment terms and a due date before a transaction is completed.  Receipt: A documnt given by the seller after the payment is completed, proof of purchase.

Policy: A rule or a set of guidlines that explains what you must do, what is allowed and why.  Process: Is the workflow map that shows the series of steps or tasks needed to get a job done and follow that rule.