We denote maxima or minima as either global or local. Simply writing maxima or minima is confusing and are taken to be the global ones by convention.
A maximum or minimum is said to be _local_ if it is the largest or smallest value of the function, respectively, within **a given range**.
However, a maximum or minimum is said to be _global_ if it is the largest or smallest value of the function, respectively, on the **entire domain of a function**.
The image shows it clearly.
![enter image description here](
You can check this video as well.