I have heard today that if any married couple have more than 12 children that breaks their marriage and they should do marriage once again. Please let us know according to Islamic law, Qur'an and hadith.
There is no limit in terms of number of kids from one couple in islam and no, you don't have to marry again after having 12 children.
Abu Dawood (2050) narrated that Ma’qil ibn Yasaar said: A man came to the Prophet (peace and blessings of Allaah be upon him) and said, “I have found a woman who is of good lineage and is beautiful, but she does not children. Should I marry her?” He said, “No.” Then he came again with the same question and he told him not to marry her. Then he came a third time with the same question and he said: “Marry those who are loving and fertile, for I will be proud of your great numbers before the other nations.” Classed as saheeh by al-Albaani in Irwa’ al-Ghaleel, 1784.
This hadeeth indicates that it is encouraged to marry women who are fertile, so that the numbers of the ummah will increase, and so the Prophet (peace and blessings of Allaah be upon him) will feel proud of his ummah before all other nations. This shows that it is encouraged to have a lot of children.