Formal:
"To the graduating class of [Year], I now have the honor of presenting you with your diplomas. These represent years of hard work, dedication, and perseverance. Please come forward to receive your diploma as your name is called."
Slightly less formal:
"Graduates, it's my distinct pleasure to confer upon each of you your high school diplomas. This is a momentous occasion, a culmination of your efforts and a launching pad for your future endeavors. Please approach the stage as your name is called."
More informal and celebratory:
"Congratulations, graduates! This is it – the moment you've all been working towards. You've earned your diplomas, and I'm so proud of each and every one of you. Let's hear it for the class of [Year]! Now, please come up and get your diplomas."
A principal might also add elements like:
* A brief congratulatory message: Acknowledging the students' accomplishments and wishing them well in the future.
* Acknowledgement of teachers and staff: Thanking the faculty and support staff for their contributions to the students' success.
* A motivating message: Inspiring the students to pursue their dreams and make a positive impact on the world.
* A joke or anecdote: To lighten the mood and make the ceremony more memorable.
The exact wording will depend on the principal's personality and the tone of the graduation ceremony.