PHP echo is a language construct not a function, so you don't need to use parenthesis with it. But if you want to use more than one parameters, it is required to use parenthesis.
The syntax of PHP echo is given below:
PHP echo statement can be used to print string, multi line strings, escaping characters, variable, array etc.
PHP echo: printing stringFile: echo1.php
Hello by PHP echo
PHP echo: printing multi line stringFile: echo2.php
Hello by PHP echo this is multi line text printed by PHP echo statement
PHP echo: printing escaping charactersFile: echo3.php
Hello escape "sequence" characters
PHP echo: printing variable valueFile: echo4.php
Message is: Hello JavaTpoint PHP