HandBrake is a tool for converting video from nearly any format to a selection of modern, widely supported codecs. The text tool is very customizable so that you can pick your own size, font type, color, alignment, and apply effects such as bolding, underlining, and italics.
You can’t truly change text or edit images using this editor, but you can add your own text, images, links, form fields, etc. It’s free as long as the PDF doesn’t exceed pages or 10 MB.