As i mentioned in the comment to the question there's no need to write custom function, because it has been written already:
Range.TextToColumns method (Excel) | Microsoft Docs[
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But if you want to return specific "word" from text, you can write a function like this:
Function SCOMPONI(stringa As String, Optional itemNo As Integer = 0) As Variant
Dim matrice As Variant, retVal As Variant
matrice = Split(Trim(stringa), " ")
If itemNo < 0 Then itemNo = 0
If itemNo > UBound(matrice) Then itemNo = UBound(matrice)
retVal = matrice(itemNo)
SCOMPONI = retVal
End Function
Usage:
B1 = SCOMPONI($A$1, 0)
C1 = SCOMPONI($A$1, 1)
D1 = SCOMPONI($A$1, 2)