What is the appropriate supplication for my 26-year-old daughter so that Allah may bless her with a righteous husband?

There is no specific supplication in Islamic law for expediting marriage. However, supplication is beneficial, by God's permission, for every permissible request, as Allah the Almighty says: "Call upon Me; I will respond to you." It is permissible to propose a woman to a righteous man whom one deems suitable for marriage, with certain regulations.