The Hindu people of India revere Lord Hanuman, a loyal disciple of the Hindu Lord Rama. Because of his undying devotion to the deity Rama. As a result, Hanuman Jayanti is celebrated on the full moon (the Chaitra Pournima) of the first lunar month (Chaitra). Lord Hanuman, a deity revered by Hindus, has his birthday, Hanuman Jayanti, celebrated every year. The attributes of Lord Siva himself—generous devotion, strength, knowledge, divine might, courage, intelligence, spirit for selfless service, etc.—are all attributed to his avatar, which is considered to be the 11th Rudra incarnation of the god.
In the states of Andhra Pradesh & Telangana, Hanuman Jayanti is the day, and the celebrations for the same last for 41 days beginning with Chaitra Purnima and concluding on the tenth day during Krishna Paksha in the month of Vaishakha. In Tamil Nadu, Hanumath Jayanti is observed during Margashirsha Amavasya, while in Karnataka, Hanuman Jayanti is understood as Hanuman Vratam.
Worshipping Lord Hanuman is enunciated to save people from evil and allow them to emerge victorious. While the festival is observed on different days in the country, most predominantly it is celebrated during Chaitra. The celebrations start early in the morning on Hanuman Jayanti as it is thought that the lord was born at sunrise. During this day, devotees read verses from Ramayana and Mahabharat and conduct other prayers as well.
They keep fast & worship god in different ways. If you are wondering how to commemorate Hanuman Jayanti, check out below the complete the Vrat (fasting) and Puja Vidhi (worship rituals) :
1. First and foremost, the day is started with Tatkalik Tithi (Ratrivyapini).
2. One night before the fast, devotees rest on the floor and worship Ram-Sita and Hanuman.
3. In the morning, again Ram-Sita and Hanuman are worshipped.
4. On this day, after getting up early, they take shower.
5. After that, they take Sankalp (oath) for the Vrat with water in one hand.
6. They are guided to sit near the east direction and face the east or north while sitting.
7. Pray for Lord Hanuman in a polite way.
8. Lastly, they worship him obeying all the practices of Shodashopachar (the 16 rites).