If you delete a record through a form you are asked to confirm the deletion. Isn't that enough?
If you just want to Report the addition then use the AfterInsert event procedure and just put:
msgbox "You have added a new record".
If you want to warn the user BEFORE the record is about to be saved, then you can ask a question in the Form_beforeupdate event procedure.
if not me.newrecord then exit sub
if msgbox ("Confirm add new record?",vbyesno) =vbyes then
' do nothing
else
cancel = true 'stop the save
me.undo ' to undo the new record, if required
end if