What is the best Du'aa after each prayer as an individual or as Imam? Please advice on the matter regarding Iddah for a woman who husband passed away. Those a woman at age 60 years included to follow Iddah?
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Supplicating Allaah is an act of worship, and a person is rewarded for supplicating Allaah, the Glorified and the Exalted. There are many forms and expressions of supplication reported from the Prophet which are said at various occasions. All the supplications that are proved in Quran and Sunnah are good and should be invoked, though some of them have special virtues. For more details on this subject read Fataawa: 84069 and 81736.
Allaah knows best.