How to invite principal on stage for speech?

It is good to keep it simple. First, say their name and title. For example, "Now, I would like to invite our principal, Mrs. Evans." Then, you can say one nice thing. Something like, "She is a great leader for our school." Finally, ask them to come up. "Please give her a very big welcome to the stage." Everyone will know to clap then. This is very clear and polite. Cheers.