She has right to claim  alimony anytime before or after divorce.

Under HMA the alimony can be claimed by filing an applicaiton under section 25 of HMA and it can be filed along with the divorce case or after the court has granted divorce 

Though wife can claim alimony anytime before or after granting divorce  but if it is claimed during pendency of divorces petition then it will be more appropriate. 

Alimony can be monthly or one time, which one is preferred by the wife  ?

What is the personal law (Hindu, Muslim or other) governing the divorce proceeding ?

If it is one time, no future alimony can be claimed .

Otherwise, it can be claimed subsequent to passing a decree of divorce.

Apologies for not providing the full information here i am talking about one time alimony and Hindu Marriage Act is my personal law.

You will need to file for independent divorce and file a separate petition seeking one time alimony.

Alimony is generally not granted to the seeking spouse if he or she is already receiving support during the time of divorce. Although the rewarding of alimony can be revised in such events based on the arguments for claiming the support.

Courts consider factors such as the length of the marriage, the financial situation of both spouses, and the standard of living during the marriage when determining alimony awards. In India, as per Laws of Alimony it can be provided to any spouse. But in most cases, it is awarded to the wife by her husband.