Filling out PDF Forms Dynamically

I have been tasked to create a php web app that merges database information with a k1 web form that was downloaded from IRS.com. Basically the pdf contains fields that the user would fill out and then either save it locally or print it out. I have a database with about a thousand people in it (of tax information prepared by our accountant) that I would like to merge the data with the PDF form acting as a template and then once it has been merged, email a copy both to our accounting department and the individual. I'm no slouch when programming with PHP, but I haven't done anything with PDF's before...can someone give me some pointers on a tutorial or outline how I should approach this? Thanks, ROn