How can I use a for each loop on an array?

A for each loop structure is more designed around the collection object. A For..Each loop requires a variant type or object. Since your "element" variable is being typed as a variant your "do_something" function will need to accept a variant type, or you can modify your loop to something like this:

Public Sub Example()

    Dim sArray(4) As String
    Dim i As Long

    For i = LBound(sArray) To UBound(sArray)
        do_something sArray(i)
    Next i

End Sub

Element needs to be a variant, so you can't declare it as a string. Your function should accept a variant if it is a string though as long as you pass it ByVal.

Public Sub example()
    Dim sArray(4) As string
    Dim element As variant

    For Each element In sArray
        do_something element
    Next element
End Sub


Sub do_something(ByVal e As String)
    
End Sub

The other option is to convert the variant to a string before passing it.

  do_something CStr(element)