Which ancient Indian text is the main source of the laws of Manu?

The ancient Indian text that is the main source of the laws of Manu is the Manusmriti.

Also called the Manava-Dharmashastra and the Laws of Manu, the Manusmriti is a Sanskrit Dharmaśāstra presenting teachings on dharma, social duties, conduct, kingship, legal procedure, punishment, inheritance, and ritual obligations. It presents itself as a discourse associated with Manu and the sage Bhrigu, although modern scholarship treats it as a composed and transmitted textual tradition rather than a single author’s simple law code.

The text is generally dated to around the 2nd century BCE to the 2nd century CE. Its manuscripts differ, and the work was not a universally applied statute book for all historical communities. British administrators nevertheless used it prominently in the eighteenth-century construction of “Hindu law,” helping give it an outsized modern reputation. The title Manusmriti means “recollection of Manu”; it is not the same as the Vedas, Yoga Sutras, or Arthashastra, though it draws on older legal and religious traditions.