If an input field asks for comma separated values, there are a couple of ways you can do so.
If the list of values you're want to input never changes, for example, if you wish to always filter Zendesk tickets by the labels "urgent" and "important" in all your recipe jobs, then you can simply type them into the input field as so:
However, if you wish to search for tickets with tags which are a variable and comes in from your trigger or a previous action, you would need to deploy some formula to enable this. As we can see below, lists of values can come either in commas-separated form, or in a list form. If they are already in a comma-separated form, you can simply pass them into a coma-separated input field.
However, if they are in a list form, then you would need to put them as such into the input field, where .join(",") essentially means to append the elements of the list together with a comma, resulting in the text string: "element1,element2,element3". If we did .join(", ") with the space behind the comma, the result set will become: "element1, element2, element3"