After your conference is over, it's important to collect feedback from the participants. However, it's equally important to get the feedback from your keynote speakers. You might use this versatile presentation feedback form template for either of those purposes.
The template below is quite lengthy, yet detailed. If you're looking to collect simple feedback, you might shorten it to a few open-ended text questions. On the other hand, if you're looking to expand that template and add more questions — consider breaking down your presentation feedback form into multiple pages.