Prints plain text

echo 'plain text'."\n";

Double quotes can parse variables

echo "Double quotes: $text"."\n";

Single quotes can not parse variables

echo 'Single quotes: $text'."\n";

Single quotes as well as double quotes can be concatenated with variables

echo 'Single quotes - '.$text." - Double quotes"."\n";

Text inside Single quotes can include double quotes as part of the text

echo 'The text includes "double" quotes as part of the text'."\n";

Text inside double quotes can include single quotes as part of the text

echo "Jane's surname is Smith"."\n";

echo can be used as a function

echo ('echo as a function')."\n";

echo can print number without quotes

echo 5 . $number;

echo

can take multiple parameters

echo 'one', 'two', 'three', "\n";

We can print multiple lines of text

echo 'Prints text 
    with multiple
lines';