PDF looks different in word than adobe acrobat?

This is not surprising, as the two formats are quite different. I would recommend you do the Mail Merge in Acrobat directly, using a script. Going back from a PDF to Word just to do a Mail Merge is not advised.

One such script is this (paid-for) tool I've created, that allows you to do it directly in Acrobat, and even automatically email the merged files to your recipients, if you wish to do so: http://try67.blogspot.com/2011/09/acrobat-mail-merge-and-email.html

You can also get it from my new website at a substantial discount, through here: https://www.try67.com/tool/acrobat-mail-merge-and-email-pdf-files

The discount code is available on the front page of the site.