OfficeTalk lets you set up one or more categories which may be used to classify your mail. To mark a mail message as belonging to a particular category, do the following:
Bring up the Mail property sheet by clicking on the received mail item or sent mail item in the Mail window using the right mouse button and selecting Edit from the context menu.
Select the Categories page. The Categories page will display a list of mail related categories in the bottom window. Each category has a check box to the left of the description.
Select one or more check boxes representing the classification of the message into the relevant categories.
Press OK to save your changes.
You may add your own private categories by typing the name of the category into the Categories window in the Categories page and pressing the Update button. The new category will appear, checked, in the bottom window. Press OK to save your changes.
If you wish to add the mail message to categories in another category set, for example, the Global category set, then select the 'Global Categories' from the Set drop down list. The list of available categories in that category set will appear in the bottom window. Select one or more categories and press OK to save your changes.
For more information on Categories, see Using Categories.