This is the foundation of an estate plan and essentially stipulates how your assets are to be distributed after you die. Unless you have a properly drawn will, your estate may not be distributed according to your wishes, but rather according to the rules of the province you live in. This may entail additional legal fees and income taxes, as well as additional delays. A will, on the other hand, specifies who your beneficiaries are and how your assets are to be divided among them, including personal property and heirlooms, guardianship, executors, legacies, trusts, etc. A will can also incorporate measures to minimize income tax in order to leave more to your beneficiaries.
A holographic will, signed by you, with no witnesses, is not recommended because it is subject to interpretation, open to challenge and may not even be recognized in certain provinces.
Pre-printed wills or computer programs, although inexpensive, are also not recommended; the savings may be insignificant compared to the potential additional cost the beneficiaries may incur in settling the estate.