Is it permissible to borrow with interest (riba) to renew the license of a taxi, which is the sole source of income for a large family, and what are the implications of this after the contract is concluded, and how is repentance performed?

Usury is one of the gravest sins and destructive acts. The Prophet, peace and blessings be upon him, cursed the one who consumes it, the one who feeds it, its scribe, and its two witnesses. It is not permissible to deal with it except in cases of dire necessity that would lead a person to perdition or an unbearable hardship, or if one cannot achieve the minimum standard of living without it. Necessity is determined by its extent and ceases when the necessity ceases.

If you were compelled to borrow with interest to license the car and found no other way, then there is no blame upon you. Otherwise, you have committed something forbidden. If you cannot terminate the contract except at a great cost, then you must repent. The money obtained is not forbidden to benefit from, because the prohibition relates to the liability of the transactor, not to the money itself.