The Ṣadaqa is a general and voluntary donation of wealth or other assets. It is not only a good deed, but also a blessing for life and the afterlife. The reward for this donation can be understood in the words of our Lord, who says:

The example of those who spend their wealth in the way of Allāh is like a seed [of grain] which grows seven spikes;
in each spike is a hundred grains. And Allāh multiplies [His reward] for whom He wills.
And Allāh is all-Encompassing and Knowing

(Sūrah al-Baqarah, Vers 261)

We learn in this verse, that Allāh rewards every donation by his means with 700 times the original value. We hope for the reward in the afterlife, but even a reward on the wealth in this life is not excluded. This we learn from the words of the prophet Muhammad (peace be upon him), who said:

The Ṣadaqa does not diminish the wealth.”
(Saḥīh Muslim)

In another tradition it says,

Allāh, the Noble, said, “donate [to the poor], children of Adam, then I will donate to you.
(Saḥīh Muslim und Buḫārī)

But Ṣadaqa does not only entail donations of wealth or assets, but every good deed among humans is a Ṣadaqa, as we learn in multiple traditions. Thus the reconciliation of persons is a Ṣadaqa, as is the speaking of good words or the teaching of useful knowledge by means of Allāh. All the things in the pursuit of the satisfaction of Allāh, which provides value to the people at the same time, can be considered Ṣadaqa.