What are the Samskaras that are still extant and applicable to all sections of Hindus society?

Our life can be compared to a Yajna, a sacrifice. Even as the implements of a sacrifice are cleaned and purified, every Hindu is expected to cleanse and purify his body and mind through certain rites. These rites prescribed for such purification are termed Samskaras (sacraments). Though these are religious rites, they have a social dimension too. The Samskaras are usually listed as sixteen.

Out of them Jatakarma, Namakarana, Annaprasana, Upanayana, Vivaha and Antyeshti are considered more important. 

Jatakarma, as its very name indicates, is the rite performed as soon as the baby is born. Medhajanana (uttering a mantra in the ear of the baby, by the father, to generate the power of intelligence and memory), prayers for longevity and good health are the chief features of this Samskara. However, this is not in vogue now.  Namakarana is the act of christening the child on the 10th or 12th day after birth. The name chosen is usually that of a god or goddess or of a saint.   Feeding the child with solid food for the first time is Annaprasana. The food should be consecrated by ceremonially offering it to the family deity before feeding the child.  With Upanayana begins a period of Vedic studies and spiritual discipline.

Hence it is considered to be extremely important. Literally, the word means leading to the Guru for education. If physical birth is the first birth, this rite gives a spiritual birth, which is the second. Hence, one who has undergone this Samskara is called a dvija (twice born). Acceptance of the loin cord and loincloth, wearing the Yajnopavita (the sacred thread), initiation into the Gayatri Mantra (also called Savitri) and begging the food these are the chief steps of this rite. 

The loincloth signifies the beginning of a life of continence and self-control. The symbolism of Yajnopavita is that from the day it is worn, life becomes a Yajna, a sacrifice, for the good of the society. The repetition of Gayatri Mantra engenders wisdom and memory, and is a great aid in the path of spiritual evolution. Begging for food impresses the novice of his indebtedness to society. He is expected to serve the society all his life and to the best of his ability in order to repay the debt.

Vivaha or marriage is considered cardinal among the sixteen sacraments. Since Garhasthya (householder's life) is the basis for all the other Ashramas, it has
been highly eulogized in the Hindu scriptural works. Satisfying lust is not the basic aim of the sacrament of marriage. Spiritual progress leading to God realization through a disciplined life in which we find self
control, companionship with the spouse and other members of the family as well as selfless service is the real aim of the married life. It is a co-operative venture of husband and wife in the field of the four Purusharthas. It is Dharma that has united them. That is why in Hinduism matrimony is considered too sacred to be dissolved. The sacrament commences with Kanyadana (gifting away the maiden to the bridegroom) by her father. Vivaha homa, offerings in a duly consecrated fire, with appropriate mantras is the next important step.

Panigrahana, the clasping of the bride's hand by the groom, which comes next, symbolizes the transfer of the responsibility of her protection from her father to the former. Saptapadi, the rite in which the couple walk seven steps together is the most important stage, which puts the legal seal on the marriage. At this point, the bride crosses over to the Gotra (lineage of family) of her husband. Suryaloka seeing the sun, is another item in the process, which indicates that the sun himself is the witness to this rite.

Asmarohana  (stepping on a block of stone) and Arundhati Darsana (seeing the tiny star Arundhati, or Alcor in the Great Bear) are two other parts of the ritual which assert that the ties of marriage should be firm and steady. Antyeshti (the last sacrifice), the last of the sacraments, is the rite of consigning the body to the fire after death. It is a sacrament performed by his relatives for his good and future well being, since he has endeavored throughout his life to Purify himself by appropriate Samskaras.

Though performed after one's death, it does not lose its significance in any way; for, in the eyes of a Hindu, after life is as important, if not more important, than life here and now. Pouring the sacred water of Ganga and offering a Tulasi leaf into the mouth of a dying person is the usual tradition. The body is then carried to the burial ground and buried or cremated according to the custom of the family. If buried, a small mound or memorial may be raised at the Place. If cremated, bones and ashes are gathered later on in an urn and consigned to the waters of a river or sea. Sraddha or obsequial rites are an important aspect of Antyeshti.

 Out of these Samskaras, only Namakarana, Vivaha and Antyesti are common to all sections of the Hindu society, though there may be variations in the details.