I am trying to "split text to column" on a .csv file in pages
In the event that the user inputs one name with no spaces, the formula in the OP could be wrapped in an IFERROR formula.

IFERROR(TRIM(RIGHT(B2, LEN(B3)−FIND(" ", B2,))),"")


The IFERROR statement returns simply and empty string "" if there are no spaces.  (No spaces returns an error because FIND() results in an error when it cannot find a space.) The formula returns the characters to the right of the space. If no spaces found, it simply returns the contents of B2. (Of course, there is no way for the computer to know if the single name entered is a first or last name, even tricky for humans.)

Something similar could be used to return the first name or just the name in the original string:

IFERROR(TRIM(LEFT(B2,FIND(" ", TRIM(B2)))),B2)


The only gotcha will be if there are several names.  But this is a good starting point. A useful resource is the Formulas and Functions Help for the Mac apps—Keynote, Pages, Numbers, and iBooks Author.  Look for Text Functions.  Good function combinations can give the desired result.  Work from the inside out.  For example, TRIM(B2) will remove all leading and trailing spaces. Then, FIND(" ",TRIM(B2)) will look for the first space without having to worry if there was a leading space.  Hope this helps!

Examples: