メソッドの引数に二次元配列を設定するには、以下のようにします。
Option Explicit
Private Sub Command1_Click()
Dim arg() As String
Dim ret() As String
ReDim arg(2, 3)
ret = testFunc(arg)
Dim s As String
Dim i As Integer
Dim j As Integer
For i = 0 To UBound(ret)
For j = 0 To UBound(ret, 2)
s = s & ret(i, j) & ","
Next
s = Left(s, Len(s) - 1) & vbCrLf
Next
MsgBox s
End Sub
'二次元配列を引数にして二次元配列を戻り値とする関数
Private Function testFunc(ByRef value() As String) As String()
Dim i As Integer
Dim j As Integer
For i = 0 To UBound(value)
For j = 0 To UBound(value, 2)
value(i, j) = i * j
Next
Next
testFunc = value
End Function