One often requested feature that is missing in older versions of Outlook is ability to insert a date and time stamp into the body of Outlook items. Beginning with Outlook 2007, Word's insert Date & Time button was added to Outlook's Insert tab; older versions will need to a custom form or an add-in to insert the date stamp.

One complaint about the Insert Date & Time command is that it is too many steps. It's not bad if you use the keyboard shortcuts: Alt+N, D, Enter will insert the date and time format you have set as default. To insert other formats, use the arrow keys to select them, then press Enter. (Home or Page Up jumps to the top entry on the list while End or Page Down jumps to the bottom.) If that is still too many steps, you can use a macro to insert the date and time.

See the Tools section below for add-ins that you can use instead. Note that the custom forms method doesn't work well with Appointment forms since you can't change the first page of the form. It also doesn't work well with contacts in Outlook 2003 and 2007 since editing the first page of the form reverts the form to the older Outlook contact form (as in the screenshot below).

Macro Method

This method uses just a macro, not a command button the form. It will work with any open Outlook item, you just need to put the macro on the Quick Access Toolbar or ribbon.

The macro can either add just the date at the top of the body field or the date and time.

Instructions to use a macro and add it to the ribbon or Quick Access Toolbar well as screenshots are at How to use the VBA Editor

Sub DateStamp()
Dim objApp As Outlook.Application
    Set objApp = Application
    On Error Resume Next
    
   Set Item = objApp.ActiveInspector.CurrentItem
  
  ' Date only
  '  Item.Body = Date & vbCrLf & vbCrLf & Item.Body
    
  'Date and time
    Item.Body = Format(Now(), "mmm d, yyyy h:nn AM/PM") & vbCrLf & vbCrLf & Item.Body
    
    Set objApp = Nothing

End Sub

Custom Form Method with Button

In a new Outlook 2003 or older, open a form then:

1. Select the Tools menu, Forms, Design this form
2. Then from the View menu, choose View code
3. In the code window, enter this code:

In Outlook 2007 and up, first show the Developer ribbon (File or Office icon, Options), then from the Developer ribbon, choose Design this form. The View Code button is in the Form section.

Sub StampDate()
   Item.Body = Now() & vbCrLf & vbCrLf & Item.Body
End Sub

Sub CommandButton1_Click() 
  Call StampDate() 
End Sub

After entering the code, close the code window.

Next:

1. Open the Control toolbox and drag a command button to the form.
2. Rename it by right clicking on it and selecting Properties.
3. In the Caption field, type in the desired name.

To use, click the button you created.

Custom Form - Automatic Method

If you want the date stamped in the Notes field every time you open an item, you can create a custom form as described above, but use the code below instead. You also won't need to add a button to the form, so it will work with contacts. Although today's date is added to the Notes field every time you open a contact, it's not saved until you Save the contact.

In Outlook 2007 and up, first show the Developer ribbon (File or Office icon, Options), then from the Developer ribbon, choose Design this form. The View Code button is in the Form section.

In Outlook 2003 and older, or Outlook 2007's main window, go to Tools menu, Forms, Design this form. Then from the View menu, choose View code.

In the code window, enter this code:

Function Item_Open()
Item.Body = Now() & vbCrLf & vbCrLf & Item.Body
End function

Publish the form and set it as the default form for the folder, if desired. If you want to use it with existing items you'll need to convert the items to use the new form. Instructions are at How to Set a Custom Form as the Default for a Folder.

How to use Macros

First: You need to have macro security set to the lowest setting, Enable all macros during testing. The macros will not work with the top two options that disable all macros or unsigned macros. You could choose the option Notification for all macros, then accept it each time you restart Outlook, however, because it's somewhat hard to sneak macros into Outlook (unlike in Word and Excel), allowing all macros is safe, especially during the testing phase. You can sign the macro when it is finished and change the macro security to notify.

To check your macro security in Outlook 2010 and newer, go to File, Options, Trust Center and open Trust Center Settings, and change the Macro Settings. In Outlook 2007 and older, look at Tools, Macro Security.

After you test the macro and see that it works, you can either leave macro security set to low or sign the macro.

Open the VBA Editor by pressing Alt+F11 on your keyboard.

To put the code in a module:

1. Right click on Project1 and choose Insert > Module
2. Copy and paste the macro into the new module.

More information as well as screenshots are at How to use the VBA Editor