If you do STRPRINT V0 V1 V2, it will add a space after every value. If you had it UNchecked, you would manually have to put the space in between as string literals " ".
Note that it adds a space AFTER EACH/EVERY element/literal/function in the STRPRINT, not just BETWEEN them. If you just wanted them BETWEEN (and not after the LAST one), go ahead and check it, but then use STRTRIM box to trim any trailing whitespace.