Do I need to make an Islamic will?

Because your local law may not apply them. In the UK, US, Canada, Australia and most of Europe, dying without a will means intestacy rules distribute your estate - and those rules do not match Islamic shares. Parents who should receive a fixed portion may receive nothing. The will is the mechanism that makes the Islamic distribution legally effective. Even in India, where Muslim Personal Law governs, a will appoints an executor, prevents disputes and directs the permitted third.

No, and this is the most common mistake. Your children, parents and potentially others have fixed shares set out in the Quran, and leaving the whole estate to a spouse deprives them of what is theirs by right. You may leave your spouse her Quranic share plus, if you wish, part of the discretionary third - but the third cannot go to someone who is already an heir unless the other heirs consent after your death.

Anyone or anything that is not already an heir. Charity, a mosque, a school, non-Muslim relatives who do not inherit under Islamic rules, adopted children who are not heirs, friends, or a cause you care about. The limit comes from the guidance that a third is already generous and that leaving heirs well provided for is better than leaving them dependent. Bequests to existing heirs need the other heirs' consent after death.