The instructions below come from Amazon’s website. I don’t own a Kindle so if you have more questions about loading a PDF file to your Kindle, I would suggest checking Amazon’s help or the documentation that came with your Kindle.
Built-in PDF reader for Kindle
Your Kindle (2nd Generation or later) device can display PDF documents without losing the formatting of the original file. Send PDF documents directly to your Kindle device (via your Send-to-Kindle address), or drag and drop PDF files from your computer to your Kindle device via USB. You can also magnify PDFs by viewing them in landscape mode.

