These days almost everything important is done online.

We live in a virtual world, where clicking a mouse in the right slot is about as complicated as things get. Even buying a property is basically done online, although there are a few documents to be signed.

Making a will is different. The formalities are important. They were first laid down in the English Wills Act of 1837 and in places, like Singapore, where English law took root, they have not really changed since.

The person who makes the will is the testator or testatrix, if a woman. He or she must sign the will at the foot, i.e., at the end of the document.

His or her signature has to be witnessed by two witnesses, who also sign at the foot at the will. (It is good practice for all three to initial the other pages.) It is important that all three – the testator or testatrix and the two witnesses – are together in the same room while the will is being executed.

A witness cannot receive anything under the will. It is important to remember this when arranging who the witnesses should be. Subject to that anyone can be a witness except the spouse of the person making the will.

Sometimes a husband and wife make what are called “mirror” wills, i.e. wills that are more or less identical to each other. In these circumstances it is important to ensure that each person signs the right will. This may seems very obvious but you would be surprised at how often it happens that husband and wife sign each other’s will, with the witnesses happily endorsing the same. It seems that in England and Australia there is legalisation enabling the court to rectify this error but the position in Singapore is untested. So get it right.

Although a will is such a formal document, it is – by definition – not effective until the testator or testatrix actually dies. So it is always possible to change a will. In the world of Agatha Christie this happens quite often. But in real life, circumstances do change: you acquire or sell assets; an executor or beneficiary dies before you: these things can make it sensible or necessary to change your will.

The simplest way to change a will is to “revoke” it – cancel it and replace it with a new one, which will expressly revoke all previous wills.

A testator or testatrix can also make additions to the will in the form of what is called a “codicil”: the same formal requirements apply as for a will.

What you must not do is start deleting and inserting words and sentences in the original will. That will only lead to confusion and possible challenges.

If you get married any will made before the marriage is automatically revoked unless it was expressly made in contemplation of that marriage.

A will is a private document but you need to ensure it is not forgotten. Your lawyer can keep the original, or a copy. In Singapore there is a Wills Registry and you can make use of that to keep an official record of the fact that you have made a will. It is not compulsory and the Registry does not keep a copy of the will.