She has some money and her father does not spend on her; does she have to pay zakaah on it?
Whoever owns the minimum amount of wealth (nisaab) and one full hijri year has passed since acquiring it, must pay zakaah, even if he is saving that money to get married or get medical treatment and so on, because of the general meaning of the evidence that paying zakaah is obligatory.
The nisaab is the equivalent of 85 grams of gold or 595 grams of silver.
If the wealth that you have is equivalent to the nisaab, then you must pay zakaah on it every time one full hijri year is completed.
The believer should understand that wealth belongs to Allaah, may He be exalted, and that zakaah does not in fact decrease wealth, rather it increases it and makes it grow, as Allaah says (interpretation of the meaning):
“Take Sadaqah (alms) from their wealth in order to purify them and sanctify them with it, and invoke Allaah for them. Verily, your invocations are a source of security for them; and Allaah is All-Hearer, All-Knower”
And the Prophet (peace and blessings of Allaah be upon him) said: “Charity does not decrease wealth.” Narrated by Muslim (2588).
How many people have wealth but never enjoy it, and how many generous givers have been blessed by Allaah with the little they have.
Charity is also a means of being healed of sickness, as the Prophet (peace and blessings of Allaah be upon him) said: “Treat your sick ones with charity.” Classed as hasan by al-Albaani in Saheeh al-Jaami’ (3358).
We ask Allaah to heal you and bless your wealth for you.
And Allaah knows best.