How to Change Case in PHP - strtolower() and strtoupper() Functions
PHP String FunctionsThe strtolower() function converts a string to lowercase and the strtoupper() converts a string to uppercase.
Syntax
strtolower(string $string)
strtoupper(string $string)
Example 1
echo strtolower("Hello, World!");
Output: hello, world!
Example 2
echo strtoupper("Hello, World!");
Output: HELLO, WORLD!