Private Sub Document_New()
Dim Rslt
With ActiveDocument.Sections(1).Footers(wdHeaderFooterPrimary).Range
  While Not Rslt Like "[1-5]"
  Rslt = InputBox("Which company's details should appear?" & vbCr & "Please input the corresponding number." & vbCr & _
      "1: Company A" & vbCr & _
      "2: Company B" & vbCr & _
      "3: Company C" & vbCr & _
      "4: Company D" & vbCr & _
      "5: Company E")
  Wend
  Select Case Rslt
    Case 1: .Text = "Company A Name" & vbCr & "Company A Address"
    Case 2: .Text = "Company B Name" & vbCr & "Company B Address"
    Case 3: .Text = "Company C Name" & vbCr & "Company C Address"
    Case 4: .Text = "Company D Name" & vbCr & "Company D Address"
    Case 5: .Text = "Company E Name" & vbCr & "Company E Address"
  End Select
End With
End Sub