If you want to share what's on your iPad screen with a large number of people in the same room, displaying your screen through a projector can be an effective solution. Options for outputting your iPad image through a projector include using AirPlay and various devices and software that support AirPlay, Apple adapters, iTools or the document camera that's build into your projector. Each option requires a slightly different mix of hardware and software.
Apple makes a Lightning-to-VGA and Lightning-to-HDMI adapter that makes it possible for you to connect your iPad to a projector to share your content with a broader audience. Both adapters output in 1080p HD and also display your video content in addition to mirroring your screen. However, these adapters don't carry your iPad's audio to the projector.
There are a host of options for getting content from your iPad to a projector through AirPlay. One option is to connect an Apple TV box to your projector and then mirror your iPad's display on Apple TV through AirPlay. Another option is to connect your computer to the projector, and then mirror what's on your iPad screen through AirPlay to third-party software, such as AirServer, Reflector or X-Mirage (links in Resources).
ITools doesn't work with AirPlay, but you can mirror the content on your iPad's screen to your computer, as long as you're connected to that computer via a Lightning cable. After your iPad content is mirrored onto your computer screen, you can connect the computer to your projector to share your computer screen.
If the projector you're using has a document camera, you can position the iPad under or in front of the document camera to share the screen. It should be noted that the images you share likely won't be as a high quality of an image as the other methods.