Microsoft word has the ability to create mail merges but we often recommend not using this function as there are a few issues with mail merges in Microsoft Word.  We prefer to use software which allows us to create mail merges within PDF documents.

The problem with word is that the program was not designed specifcally to create mail merges.  Using a PDF software give much more control over the merge and allows for many additional functions.  PDF software allows additional rules to be created, and essentially any rule can be coded into the document.  Some examples are dynamic changes to formatting, change to fit options, variable imagery, etc.  It is also much better to print variable data from a PDF, as opposed to printing from a word file.  

PDF software also allows more options to review the merge to make sure nothing is being truncated or causing unintended changes in the document.  Microsoft word documents often change depending on the settings on each computer.  The alignment and design of the document can also be difficult to control especially with variable data being inserted into the document.

Though we highly recommend using setting up variable data mail merge documents in a PDF software, we can and do use microsoft mail merges for some mailing.  This should only be done for simple merges with address merge and perhaps a variable salutation.  Everything else we recommend using PDF software.  The best way to set something like this up is to send a PDF document with either notes or highlighted fields that indicate the merged field and any other notes indicating special requests.