Mahiya is a three-line form. The first line sets an image, usually of no importance, the third rhymes with it and carries the meaning. The gap between them is the whole art.
Tappe are two-line couplets sung in a fixed high melody, traded back and forth between singers or between a bride's side and a groom's side at a wedding, often competitively and often rudely.
Dhola is the long-line lament of the south-western districts, sung slowly and unaccompanied or with a single string.
Sithniyan are the abusive songs sung by the women of a bride's family at the groom's party, which are formally required, are extremely direct, and are received with laughter. Refusing to sing them would be the insult.
These forms are composed by anyone and belong to nobody. They are the base layer under all Punjabi music, and every commercial Punjabi song of the last fifty years is built on one of them.
The mahiya is a three line form with the first line usually an image and the last two the statement. It is sung by women and by men, at work and at weddings, and it is improvised.
The tappa is shorter and faster and is the form that carries the contest, two singers answering each other on the same tune with different words.
The dhola is the long form of the west, sung in the bar country and in the Saraiki belt. None of the three has been collected systematically on the Indian side.