ShortPixel wordpress plugin is one of the most popular image optimization plugins and with good reason. It i easy to set up and handle and the compression is remarkable if you chose lossy compression. It is possible to create webp image files on the fly and show them on your website in a combination with Cache Enabler.  Another option included in ShortPixel is via htaccess to grab webp images created by Shortpixel and use them instead of jpg and png images. This website uses this technique.

ShortPixel comparision of original image and lossy compression