Here is a VBA way, add it to a module & =PrefixCaps("A1")
Public Function PrefixCaps(value As String) As String
Dim Words() As String: Words = Split(value, " ")
Dim i As Long
For i = 0 To UBound(Words)
Mid$(Words(i), 1, 1) = UCase$(Mid$(Words(i), 1, 1))
Next
PrefixCaps = Join(Words, " ")
End Function