Story of the birth of Goddess Saraswati in the Brahmanda Purana begins with Brahma, the Hindu God of Creation, preparing for a yajna, or sacrifice. Her presence was vital for the success of the yajna.
Brahma summoned Goddess Saraswati from his mind in order to successfully complete this very important yajna he was performing prior to the creation of the universe.
A girl appeared from the Sattva Guna of Brahma.
He named her Saraswati and asked her to stay on the tip of the tongues of human beings.
She was also asked to take the form of a river on earth.
In a third form, she remained with Brahma forever.
After creation, sages venerated her as the patron goddess of ceremonies. Her guidance and blessings were sought for the proper completion and success of yajnas.