If you're using WhatsApp on your iPhone, you may need an easy way to save WhatsApp message history to printable format for various purpose. iBackup Viewer is the exact app to do such work for you. What you need to do is just few clicks.
Create a backup for your iPhone with iTunes.
Installer and run iBackup Viewer.
Then choose the backup you've created with iTunes in the left side navigation panel, expand it and select "WhatsApp".
Open the "Export" drop down menu, choose "Current Thread to PDF..." if you'd like to save the messages to PDF file
or "All Threads to PDF..." to save all conversations to separate PDF files.
Optionally, you can save the messages to well formatted HTML files by selecting "Current Thread to HTML..." or "All Threads to HTML..."