There are broadly three types of wills: a holographic will, an English will and a last will and testament. The first, you can do in the comfort of your home, and it means you write in your own hand what you would like to happen to your assets after you die. It would be useful to date this and keep it in a safe place, and possibly have someone else sign too as a witness, to indicate that he/she saw you write and sign it yourself.
The second and third are done through your notary. The will and testament is done in a law office or with lawyers present in another location. Some lawyers visit their clients in their residences, for example, if they are too old and weak to make the journey into the law office themselves. There must be two lawyers present to notarise the will, and the executing lawyer will guide you as to how to structure and set up the will. However, he or she will not advise you on whom to leave your money, property and/or other assets. This is entirely your decision; the lawyer is merely there to take instructions from you.
If your circumstances change, for example, you get married (or divorced); someone you bequeathed your assets to or the executrix has died, you MUST consider updating your will. This will avoid confusion later (pardon the pun). The last thing you would want is some indecision in terms of what happens to your assets and your instructions being unavoidably ignored.
It is entirely up to you if you wish to let the persons you will leave monies and/ or property to; know of your decision before you pass on. In some cases, it would simplify the execution of the will, as the parties will be known to the lawyers or the witnesses. Sometimes, pets have been left items as well, or in the care of others. It is important that the instructions left in the will are honoured as much as possible to respect the individual who has gone.