Durga is worshipped in different forms. She is a form of "Shakti". The evolution of Shri Maha Saraswati, Shri Maha Laxmi and Shri Mahakali (the 3 main forms of "Shakti") took place from Shri Brahma, Shri Vishnu and Shri Mahesh respectively. Each of these 3 deities gave rise to 3 more forms and hence in all, these 9 forms together are known as Nav-Durga.
Goddess Durga has nine names as follows: shailputri, brahmcharini, chandraghanta, kushmanda, skandmata, katyaini, kaalratri, mahagauri, and siddhatri. In Navratri, worshiping all these forms of Goddess Durga is important. Navratri puja is started with the Kalash Sthapana. According to Hindu customs, Kalash is considered to represent Lord Ganesha, therefore the puja is started with chanting lord Ganesha's mantra. Thereafter, different forms of Goddess Durga is worshipped by these following mantras.
Vande Vanchhit Laabhaay, Chandrardhkritshekharaam |
Vrisharudham Shooldharaam Shailputriim Yashaswinim ||
Meaning: I worship Goddess Shailputri to fulfill my wishes, who is adorned with crescent moon on her head, rides on a bull, carrying a trishul and is illustrious.
Dadhaanaa Kar Padmaabhyaamakshmala Kamandaloo |
Devi Prasidatu Mayi Brahmcharinyanuttamaa ||
Meaning: O Goddess Brahmcharini, who holds rosary and Kamandalu in her hands, please on me.
Pindaj Pravaarudh chandkopastrkairyuta |
Prasadam Tanute Madhyam Chandraghanteti vishrutaa ||
Meaning: O Goddess Chandraghanta, who rides on Tiger, angry on enemies, holds many weapons in 10 hands, be propitious to me.
Suraasampoorna Kalasham Rudhiraaplutamev Cha |
Dadhaanaa Hastpadmaabhyaam Kushmanda Shubhdaastu Me ||
Meaning: Goddess Kushmanda who holds two pitchers full of Madira and Blood in her lotus hands, be propitious to me.
Sinhaasangataam Nityam Padmaanchit Kardwayaa |
Shubhdaastu Sadaa Devi Skandmata Yashaswini ||
Meaning: Skandmata, who rides on Lion with Kartikeya, holds lotus in her two hands and Varmudra in one hand, be propitious to me.
Chandrahaasojjval Karaa Shaardoolvarvaahanaa |
Katyayani Shubham Dadyaad Devi Daanavghatini ||
Meaning: Devi Katyayani, who holds Chandrahaas Sword and other weapons in her ten hands, rides on Lion, and destroying demons, be propitious to me.
Ekveni Japakarnpoora Nagna Kharaasthita |
Lamboshthi Karnika karni Tailaabhyaktshariirini ||
Vaam Paadollasallohlata Kantakbhushanaa |
Bardhan Moordham Dhwajaa Krishnaa Kalratrirbhayankari ||
Meaning: This mantra describes her form. She is naked, rides on an donkey, long tongue, lustrous body, wearing ornaments in legs like lightning, black in color, unlocked hair, big eyes and ears and very dangerous looking. Meditating on this form of Kalratri removes all obstacles as well as removes all magical effects created by others.
Shwete Vrishesamarudha Shwetaambardhara Shuchih |
Mahagauri Shubham Dadyanmahadev Pramodadaa ||
Meaning: Goddess Mahagauri who rides on white bull, wear pure white clothes, giver of happiness, be propitious to me.
Siddha Gandharva Yakshdyairasurairamarairapi |
Sevyamaanaa Sadabhuyaat Siddhida Siddhidayini ||
Meaning: Goddess Siddhidatri who is worshipped by Siddha, Gandharva, Yaksh, Gods, Demons etc., holds Conch, Chakra, Gada and Lotus in her hands, giver of all siddhis and victory all over, be propitious to me.