In PHP, single quotes and double quotes work differently.
When you use single quotes, PHP treats the content as a literal string, so variables are not interpreted.
For example, in single quotes, 'Hello, my name is $name.' will display exactly as it is, without replacing $name with its value.
However, with double quotes, PHP will replace variables inside the string.
For example, "Hello, my name is $name." will display "Hello, my name is Ben.".