Saranagathi as Mokshopaya.

Prapatti marks an intense state of Bhakti. It is known severally as Nyaasa, Tyaaga, saranagathi, Prapadana, Atma Nikshepa and Bharanyasa. All these mean seeking refuge at the Feet of the supreme as the Mokshopaya.
Saranagathy as an Upaya for Moksha is one of the most effective means. the Taittiriya Upanishad lists out in the ascending order of effectiveness, the different paths leading to Moksa.

Satyam                                  : Practice of Truth.
Tapas                                    : reducing bodily needs.
Dama                                    : Control of one's outer senses.
Sama                                     : Control of one's inner sense.
Danam                                   : Liberaly donating one's wealth.
Dharma                                  : Practice of one's duties.
Prajanana                               : Begetting children.
Agneyah                                 : Offering to the Devas through fire.
Yajna                                     : Sacrifices.
Maanasa                                 : Meditation on God.
Nyasa                                     : Surrender.

the said upanishad also refers to Nyasa as Devaanaam Guhyam: i.e. the devas regard Nyasa as a top secret. the scriptures says Nyasa is Saakshaat Moksha upaya. i.e. direct means to Moksa.

The main aspect of Prapatti marg are popularly known as Shad (six) Angas as against ashtanga yoga of Patanjali.
The five angas are:
Aanukoolya Sankalpa
Pratikoolya Varjana.
Mahavishvasa.Goptritva Varana
Aatmanikshepa
Kaarpanya or Aakinchinyam.