Absolutely!

To add comments within a formula tool you can either add two forward slashes "//" to the beginning of your comment OR open your comment with forward slash and star "/*" then close it with a star and forward slash "*/".

Examples:

// Here is a comment in a formula tool

/* Here is another comment in a formula tool */

You may also take advantage of the built-in Comment Tool in Alteryx which can be handy if you want to see a comment without having to click on the formula tool.