All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Iddah is a waiting period which a woman observes in her husband`s house because he divorced her or he passed away. She does this in compliance with Allah`s command in this regard, and to make sure that she isn`t pregnant or to mourn husband. In principle, a woman observing Iddah must stay at husband`s house until her Iddah expires.
However, some Maliki jurists are of the view that it is permissible for her to leave house during the day, even for no need. It was stated in the Maliki book {Minah Al-Jaleel, 4/335}, "It is permissible for the woman observing iddah, because she was divorced or her husband passed away, to leave her house-from dawn to sunset-for a need…..It is also permissible that she leaves during day time for no need…..However, she may not spend the night save in her house."
Maliki jurists have based this opinion on the Hadith in which Jabir b. 'Abdullah (Allah be pleased with them) reported: "My maternal aunt was divorced, and she intended to pluck her dates. A person scolded her for having come out (during the period of 'Idda). She came to Allah's Prophet (may peace be upon him.) and he said: Certainly you can pluck (dates) from your palm trees, for perhaps you may give charity or do an act of kindness."{Related by Muslim}. Also, Abdullan ibn Umar said, "The only place a woman whose husband has died and a woman who is absolutely divorced can spend the night is in their houses."{Malik}. Whatever is said by a companion on issues where there is no room for Ijtihad{Independent reasoning} is acceptable to all scholars. As regards the majority of the scholars, they are of the view that it isn`t permissible for the woman observing Iddah to leave husband`s house save for a need.
In conclusion, it is permissible for the woman observing Iddah to leave husband`s house to work or to pay an important visit, but in moderation, on the condition that she spends the night at the house where she is observing Iddah. As for travelling, she isn`t allowed to do that. And Allah knows best.