You can see a list of all the built-in functions on the perlfunc main page. Almost all functions can be given a list of parameters , which are separated by commas. The print function is one of the most frequently used parts of Perl. It takes a list of things to output as its parameters. The only thing you need to know is that you never insert commas or spaces into numbers in Perl.
Strings are a bit more complex.
If functions are Perl's verbs, then variables are its nouns. Scalars are single things. This might be a number or a string. We the People, etc. The conversion happens automatically.