Well, generally speaking you would create a table to hold the modified data. You might have 3 fields
then in a sub, you could have this code.
Dim rst As DAO.Recordset
Dim fldName As String
Dim ctl As Control
Set rst = CurrentDb.OpenRecordset("tblModified", dbOpenDynaset)
If Me.NewRecord Then
If Me.Dirty Then
For Each ctl In Me.Controls
If ctl.ControlType = acTextBox Then
rst!FieldName = ctl.Name
rst!DateMod = Now()
rst!txtOldValue = ctl.OldValue
Then you would call this code from the AfterUpdate event for each control you want to keep track of changes in.