Is an unregistered marriage, contracted without the presence of the guardian (wali) or any family member, with only two witnesses and without the pronouncement of the marriage formula, considered Islamically valid, and what should be done about it?

The marriage contract mentioned is invalid due to the absence of a guardian (wali), which is the opinion of the majority of jurists, and due to the absence of the verbal صيغة (formulation) of offer (ijab) and acceptance (qabul). A contract is not valid through writing alone according to the majority. According to the Hanafis, it is not valid between those who are present. Therefore, the couple must be separated. If they wish to marry, they must renew the contract with its lawful conditions: the guardian, verbal offer and acceptance, and witnesses.