The obligatory details
The date of issue — under article 139 of the Civil Code, a power of attorney without it is void. Also: the details of the principal and the representative, the list of the powers and the signature.
A power of attorney is given for a term of not more than three years. If it states no term, it holds for one year from the day of issue.
When you need a notary
Under article 135 of the Civil Code, a power of attorney for transactions that require notarial form, or for acts towards legal entities, must be certified by a notary. The exception is the cases where the legislation sets another form.
For example, a contract for the sale of a house, a flat or a part of one (article 488 of part two of the Civil Code) and a contract for the gift of immovable property (article 504) need notarial certification. So a power of attorney for such transactions also needs notarial certification.
Write the powers exactly
The wording "to settle all questions" is dangerous. List every power separately: in which body, on which documents, up to which sum.
Revocation
Under article 141 of the Civil Code, you can revoke a power of attorney at any time. Under article 142, you must tell the representative and the third persons known to you, for whom the power of attorney was given, about the revocation.