Let's say you have a variable that contains fruit.

$fruit = "banana apple orange grape";

The .= operator can be used to append values to the end of the variable. In this example, pineapple will be appended to the $fruit variable.

$fruit .= "pineapple";

The variable can be printed.

echo $fruit;

The original values in the variable plus pineapple will be printed.

banana apple orange grape pineapple