My question is: If a widow whose husband passed away was staying in rented home or in a different country but has to move out during the Iddah period and has no choice due to her circumstance. What should she do? Is it Halaal to move out?

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.

In principle, it is not permissible for a widow in her waiting period to move from the house where she was living when her husband passed away without a valid and sound reason. However, if she is obliged to move, then there is no harm on her, as Allaah says (what means): {…while He has explained to you in detail what is forbidden to you, except under compulsion of necessity?} [Quran 6:119]

Allaah also says (what means): {…and has imposed no difficulties on you in religion} [Quran 22:78]

Moreover, the author of Az-Zaad, Imaam Ibn Al-Qayyim said regarding a woman in her waiting period who moves out of her deceased husband's house: "If she is afraid, or if she is forced to move, or because of a valid religious reason, then she can move to wherever she wishes." However, some scholars set a condition that she should move to the nearest house to her deceased husband's house.

Allaah Knows best.