Is it considered fornication for a man to have sexual intercourse with his former wife after her waiting period has ended and they have informally agreed to reconcile, but before the legitimate marriage contract has been finalized?

Marriage has pillars without which it cannot be contracted: the presence of the woman's guardian or his representative, two just witnesses, and a formula indicating the contract. The schools of thought differed on the sufficient formula. The Hanbalis and Shafi'is stipulated a word derived from "tazwij" (marrying) and "inkah" (marrying), while the Malikis and Hanafis permitted what indicates perpetuity, such as "ankahtu" (I have married) or "mallaktu" (I have given possession). There is also an opinion that validates marriage with any formula that people customarily consider a marriage. If the formula used is among those that validate marriage according to the detailed explanation, then it is a valid marriage. Otherwise, it is not sufficient according to the majority of scholars, but it is not considered zina (fornication) due to the presence of a semblance of marriage, and it is safer to renew it. Reciting Al-Fatiha or documenting the marriage with an authorized officiant are not conditions for its validity.