Many people either want to build a new house or extending an existing one. If there is not a brick supply company in your area, you can act as a agent by buying, adding a markup and supplying people in your area with concrete blocks and clay bricks.
This is a retail business model where you buy the brick add a profit and resell it. You don’t have to hold stock, you can just keep samples and get orders and then arrange delivery.
Should you not make your own bricks?
Only if you have existing capital to buy the correct machines and space to produce enough quantity to make it viable. Producing bricks is hard work and won’t be very profitable if you cannot product volume. You would be better off reselling. Although this guy looks pretty happy making bricks himself: