There are three different kinds of divorce.
At-Talaaq Ar-Raj’ee (Revocable Divorce)
This is the divorce where it is permissible for the husband to return to the wife without her consent. If either of the couple were to die during her Iddah, the remaining one is part of the group that will inherit the dead spouse.
This is when the husband has divorced the wife and she has completed her Iddah, whereby he can only marry her again with another Nikaah.
This is when marriage is forbidden between the couple, until the woman marries another man, because her husband has divorced her three different times. According to the words of Allaah:
“A divorce is only permissible twice, after that the parties should either hold together on equitable terms, or separate with kindness” (Q2[Baqarah]:229).
And He says again:
“So if a husband divorces his wife (irrevocably) he cannot, after that, re-marry her until after she has married another husband and he has divorced her.” (Q2[Baqarah]:230).
D: Taking Witness During Divorce
The generality of scholars hold the opinion that divorce is valid without witnesses because divorce is the right of the husband; therefore he does not require any witnesses to discharge his right. They also state that there is no hadeeth of the Prophet that legislates witness during divorce.
However, some scholars among the Companions and others held the position that taking a witness is compulsory before divorce or else the divorce is not valid. Among the companion is Commander of the faithful Ali ibn Abi Taalib and ‘Umar ibn Hussain. Among the Tabi’een are: Imaam Muhammad Baqir and Al-Imaam Ja’far Sadiq A’Tawoos, Ibn Juraij, Ibn Sireen etc.
It was reported that Ali told someone who asked him about divorce: “Did you have two just witnesses (men) as Allaah commanded you?” He responded, “No.” Ali told him, “Go away your divorce is baseless.”
Their evidence is the saying of Allaah:
“Thus when they fulfil their term appointed, either take them back on equitable terms. And take for witness two persons from among you endured with justice, and establish the evidence for the sake of Allaah.” (Q65[Talaaq]:2).
According to Ibn Taimiyah: “The meaning of ‘parting with them’ is to let her go after she has completed her Iddah and this is not divorce nor returning to marriage. To have witness in this is generally accepted among Muslims, because the witness is when he is taking her back, not when he is divorcing her.” Allaah knows best.