A witness to a will should be:
The witnesses do not have to be independent of each other. So, for example, you can ask a husband and wife each to be witnesses.
It is important that neither of the people witnessing your signature of your will, nor their spouse or civil partner, receive any sort of benefit under your will. However, if your witnesses are professional trustees or executors, and are charging for their services, then this restriction does not apply to their professional charges.
The witnesses must understand what it is they are witnessing. This means that they need to understand that they are witnessing your signature on a document. It doesn’t mean that they need to know the contents of the will, and it doesn’t even mean that they have to know it is a will. But you should not mislead them into thinking it is something else, if there is reason to suppose that they would not have signed it if they had known what it was.
If at a later date the signing of your will is called into question, the witnesses may be asked about it, and will need to be capable of giving evidence in relation to it. For this reason, you may consider asking people other than close family members to be witnesses. And you’ll need to be sure that those you do ask have sufficient mental capacity to understand what they are doing.
A blind person cannot be a witness to a will.
You must sign your will in the presence of at least two witnesses, both of whom are present to witness it at the same time.
The executors of your will can also be the witnesses to your will, so long as they satisfy the usual criteria referred to above. If the executors are also beneficiaries under your will, you should consider asking someone else to act as a witness. This is because a witness to a will generally cannot benefit from it.
If you ask a beneficiary of your will to also be a witness to it, then any gift you may have made in your will to them may fail. This will have no bearing on the validity of the rest of your will. The general rule, therefore, is that beneficiaries shouldn’t also be witnesses. But, as with many rules, there are some exceptions:
Despite the fact that there are some exceptions, they are largely to do with circumstances which have changed after the will has been made. As a rule, you should therefore not ask anyone who is going to be a beneficiary to witness your will.