Issue Creating Autofill Macro with a VBA Function - vba

Question

I am having an issue creating a macro that will autofill a VBA function named "FindMyOrderNumber". Every time I run a macro to Autofill "FindMyOrderNumber" only the first cell in the column is populated.
This function will look up an order number in column A (A1) and return the name of the worksheet it can be found B (B1).
Option Explicit
Function FindMyOrderNumber(strOrder As String) As String
Dim ws As Worksheet
Dim rng As Range
For Each ws In Worksheets
If ws.CodeName <> "Sheet3" Then
Set rng = Nothing
On Error Resume Next
Set rng = ws.Cells.Find(What:=strOrder, LookAt:=xlWhole)
On Error GoTo 0
If Not rng Is Nothing Then
FindMyOrderNumber = ws.Name
Exit For
End If
End If
Next
Set rng = Nothing
Set ws = Nothing
End Function
I created this macro to enter my VBA function "=findmyordernumber(a1)" in cell B1 then to Autofill column B.
Sub AutofillVBAFunction()
Range("B1").Select
ActiveCell.FormulaR1C1 = "=FindMyOrderNumber(RC[-1])"
Selection.Autofill Destination:=Range("B1:B68")
Range("B1:B68").Select
End Sub
After I run this macro only B1 is populated.
Sorry if this has been discussed I am new and I tried How to fill-up cells within a Excel worksheet from a VBA function? and other questions and I could not apply it to my issue.
Please help

Answer 1

Add application.volatile to the function, that way it will calculate as the sheet changes.
Function FindMyOrderNumber(strOrder As String) As String
Dim ws As Worksheet
Dim rng As Range
Application.Volatile
For Each ws In Worksheets
If ws.CodeName <> "Sheet3" Then
Set rng = Nothing
On Error Resume Next
Set rng = ws.Cells.Find(What:=strOrder, LookAt:=xlWhole)
On Error GoTo 0
If Not rng Is Nothing Then
FindMyOrderNumber = ws.Name
Exit For
End If
End If
Next
Set rng = Nothing
Set ws = Nothing
End Function
It also wouldn't hurt to calculate the sheet when You add the formula to the range.
Sub Button1_Click()
Dim Rws As Long, Rng As Range
Rws = Cells(Rows.Count, "A").End(xlUp).Row
Set Rng = Range(Cells(1, 2), Cells(Rws, 2))
Rng = "=FindMyOrderNumber(RC[-1])"
End Sub