In what two ways, based on the number of shares transacted, do brokers typically charge for executing

Question:

In what two ways, based on the number of shares transacted, do brokers typically charge for executing transactions? How are online transaction fees structured relative to the degree of involvement?
Broker
A broker is someone or something that acts as an intermediary third party, managing transactions between two other entities. A broker is a person or company authorized to buy and sell stocks or other investments. They are the ones responsible for...