What is the difference between the graph of a exponential growth function and an exponential decay function?

is increasing
Here’s ##y=2^x## :
graph{y=2^x [-20.27, 20.28, -10.13, 10.14]}
is decreasing
Here’s ##y=(1/2)^x## which is also ##y=2^(-x)##:
graph{y=2^-x [-32.47, 32.48, -16.23, 16.24]}