When sending a standard letter to a constituent, you can custom the letter to be specific to the constituent by using mail merge in Microsoft Word.
To create a mail merge document:
1.    Create 
 a generic letter or form in the Microsoft Word format that will be used 
 for the merge letter.
For example:

2. Create a new standard letter setup.
3.    From 
 the Standard Letter Maintenance screen, click Create/Edit 
 Mail Merge Template from the Common Tasks category.
Personify displays a message asking if you want to modify an existing Word 
 mail-merge template.
4.    Click 
 Yes.
The Browse window displays.
5.    Navigate 
 to the document created in step 1.
The document opens in Microsoft Word.
6.    On the Mailings tab, click the 
 Insert Merge Field button 
 to open the popup with the list of Personify fields, as shown below.
 
7. Select either the Address Fields or Database Fields radio button to narrow the results.
8.    Select 
 the appropriate field that you want in your standard letter and 
 drag it onto the right spot in the document, as shown below.

9.    Click 
 Preview Results to see how the 
 data will look in the merged document.  
Click Preview Results again to see the field names.
10. Click Save.