A young man becomes bar mitzvah, or a Son of the Commandments, when he reaches age thirteen, with or without ceremony. When there is a ceremony, the young man is called to the Torah.

A young woman becomes bat mitzvah, or obligated to follow the relevant
commandments of the Torah, when she reaches twelve years and a day, with or without ceremony.

Here are Bat Mitzvah place cards, envelope, and invitation made from set 02007 Bat Mitzvah (standard and custom sheets):

Note that the invitation could also be a program cover.

Here are a Bar Mitzvah envelope, place card, and invitation made from set 03136 (standard and custom sheets):

It is customary for a young man to be given an aliyah during the Torah reading on the Shabbat following his thirteenth birthday. He may have the honor of carrying the Torah scroll around the synagogue before the Torah reading.

In Reform and Conservative synagogues, young women celebrate their bat mitzvahs in exactly the same way as young men celebrate their bar mitzvahs, and at the same age, thirteen.

The first woman to celebrate a bat mitzvah was Judith Kaplan, daughter of Rabbi Mordecai Kaplan, the founder of the Reconstructionist movement.

Many women who had no opportunity to have bat mitzvah ceremonies as children study Judaism as adults, and elect to celebrate their bat mitzvahs.