Heard of the Naraka called Punnama. Is there any description of how the Naraka will look like? How the soul in that Naraka can be liberated? What are the ways to avoid that Naraka?
According to Manusmṛti, it's a special hell reserved for sonless parents:
punnāmno narakād yasmāt trāyate pitaraṃ sutaḥ |
tasmāt putra iti proktaḥ svayameva svayambhuvā || 9.138 ||
Because the Son delivers his father from the hell called Put, therefore has he been called Putra, Deliverer from Put, by the Self-existent One Himself. — (9.138)
Medhātithi, however, doesn't interpret the verse literally. He says naraka simply refers to the form of life the sonless man will take in his next birth on Earth:
This is a declamatory supplement to the Injunction of begetting children.
'The hell called Put'—is the name given to the four kinds of elemental life on the Earth. And from this is the father delivered by his son, as soon as he is born; which means that he is born next in a divine life.
It is for this reason that he is called 'Putra,' 'Deliverer from Put.'—(138)
What are the ways to avoid that naraka?
Niyoga (if the man is impotent or has a deadly disease)
On failure of issue, the woman, on being authorised, may obtain, in the proper manner, the desired offspring, either from her younger brother-in-law or from a Sapiṇḍa.—(9.59)
If a son is born of the wife of a man, either dead or impotent or diseased, by one who has been duly authorised,—that son is declared to be kṣetraja, soil-born.—(9.167)
Take another wife (who can deliver a son).
Āpastamba (Aparārka, p. 100).—‘So long as one's wife is endowed with virtue and offspring, one shall not take to another wife; if she be wanting in either of the two, he shall take to another.’