how to make string capital in php code example

Example 1: php string to uppwe

$lowercase = "this is lower case";
$uppercase = strtoupper($lowercase);

echo $uppercase;
// THIS IS LOWER CASE

Example 2: php uppercase

//string to all uppercase
$string = "String with Mixed use of Uppercase and Lowercase";
//php string to uppercase
$string = strtoupper($string);
// = "STRING WITH MIXED USE OF UPPERCASE AND LOWERCASE"

Example 3: first character uppercase php

ucwords("hello world"); // Hello World
ucfirst("hello world"); // Hello world

Example 4: php uppercase first letter

ucfirst($myword);