Before I get started with what you should write I would like to clarify what perhaps he should not. If you make a reference to G-d it should be spelled as I just did missing the middle letter.
Perhaps you are wondering why?
The reason is that bar mitzvah invitations can frequently be thrown in the garbage. It is not respectful to dispose of a piece of paper with G-d’s name on it in a garbage. In fact manyold holy Hebrew books such as the Bible are disposed of by burial in a traditional Jewish cemetery.
Let’s get back to the topic at hand of bar mitzvah invitations wording. It is common to express one’s gratitude to being able to celebrate this happy occasion. So a good sample of this would be: “With pride and joy it is our great pleasure to invite you to share this special day with us”. You will also want to mention briefly the purpose of the invitation is to worship and if appropriate mention that the boy will be “called to the Torah”.
Although the most memorable part of a bar mitzvah for many may be the party after the ceremony. It is important that the Bar Mitzvah invitation focuses on both the ceremony and that who what and where that happens afterwards.
Remember to get a proof from the printer of your bar mitzvah invitations wording so you can review it and make sure that everything is correct. If you are new to the formalities of a Bar Mitzvah you may want to show the proof of your bar mitzvah invitation to your Rabbi or Bar mitzvah teacher.
Please note that many of the above points may apply to a Bat Mitzvah for a girl as well.