The basic principle is that
it is impermissible for a wife to give away charity from her husband's money without his permission, except for what is customary, such as what is being given to the neighbors, beggars and such like, in a way that does not harm her husband. The reward in this case will be divided between them, for the saying of the Prophet (peace be upon him),
Whenever a woman gives away (for charity) some of the food in her house, without causing any mischief, she will be rewarded for whatever she has given, and her husband will also be rewarded for what he has earned. The same applies to a trustee, as in no respect does one diminish the reward of the other.
(A report whose authenticity was agreed upon by Al-Bukahri and Muslim.)
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.