Hanuman is born to a couple who are pious devotees of lord shiva. His mother is anjani and father is kesari. Kesari was very brave and also ardent devotee shiva. Hanuman was their only child. He was mischievous during his childhood and latter became the disciple of sun god (surya deva).
As a gratitude to his guru surya deva, he went on to serve lord rama who is born in the family surya vamsha. This mean Ram was the descendant of members of surya deva family lineage.
Hanuman with lord Rama: Hanuman became a sincere devotee to lord ram and helped him in tracing godess seeta devi who was hidden in lank by demon king ravan. To build a bridge over sea, hanuman is said to have found a method to float stones on ocean water. When he wrote “Shri Ram” on the stones and threw them over water, they did not sink floated instead. Then the entire vanara sena (monkey soldiers) completed the whole bridge to cross the sea.
This bridge is still present to this day as Ram setu.
Lord hanuman is also called as chiranjeeva. This means he is ever alive and has no death.
When lord ram and laxmana are about to leave for their divine abode, lord hanuman wanted to accompany. But it is said lord ram insisted to stay back and help devotees. Hence he is also called as kalyuga brahma as he can bless anyone with their genuine wishes.
Even there are few hindu saints who claimed to have seen lord hanuman. One of them is tulsidas, who wrote hanuman chalisa. One can find lord hanuman in groups where lord ram bhajan and worship is happening.
Hanuman Mantra: There are few mantra of hanuman written by different saints. I personally go through hanuman chalisa. The recitation of mantra help overcome mental agony, health problems and also helps improve your luck.