There are three different methods of dissolving a marriage:

1- Divorce initiated by husband; it is known as Talaq

2- Divorce initiated by wife – known as Khul`

3- Divorce initiated by the judge in a court of law

 

Each of these forms of divorce is valid as long it fulfills the conditions of valid divorce.

 

Regarding to the specific question you have raised about talaq al-tafweez, it is also valid; it means that a husband delegating divorce to his wife so that she is free to do so. For example, at the time of marriage, a husband can say: I grant you the authority of divorce, in case you choose to do so. In this case, she is allowed to do so.

 

However, since divorce is the most hated of all permissible things in Islam, we are not to resort to it for frivolous reasons: We ought to keep the marriage unless circumstances warranting it:

 

For details, please consult the answer linked here:

 

Valid Reasons for Divorce in Islam

 

Lastly, a man or woman can also delegate the authority to dissolve the marriage, when circumstances warrant it, to a third party: a guardian or any other reputable person.

 

It is called tawkil or delegation.

 

You may also refer to the detailed answer in regards to the procedure of divorce in an earlier question on this session.

 

Almighty Allah knows best.