There are numerous factors that will change the demand for a good/service, irrespective of the price level. Collectively these factors are called the conditions of demand
Changes to each of the conditions of demand, shifts the entire demand curve (as opposed to a movement along the demand curve)
A graph that shows how changes to any of the conditions of demand shifts the entire demand curve left or right, irrespective of the price level
For example, if a firm increases their Instagram advertising, there will be an increase in demand as more consumers become aware of the product
This is a shift in demand from D to D1. The price remains unchanged at £7 but the demand has increased from 15 to 25 units