What is Sadaqah Jariyah?
On the authority of Abu Hurairah (ra) that the Messenger of Allah (saw) said, ‘When a person dies, his deeds come to an end except for three: Sadaqah Jariyah (a continuous charity), or knowledge from which benefit is gained, or a righteous child who prays for him’. (Muslim)
Sadaqah Jariyah literally means ‘a continuous, ongoing, flowing charity’. While Sadaqah benefits the person who receives it on one occasion, Sadaqah Jariyah continues to benefit the recipient(s) for a long time.
Thus, you will receive countless rewards for a single donation, even after you have passed away. You can even give on behalf of a deceased loved one, as they will continue to gain reward from it for as long as people benefit from it.