Is one sinful for taking money from a partner without his knowledge due to shyness, believing that he has the right to do so because he did not receive financial compensation for his work, and is it permissible for him to give this money as charity on behalf of the partner, or to give it to his son as phone credit?

The questioner erred by taking the money without the knowledge of his father's partner, because the money was no longer exclusively his father's property. The questioner must return the money to the store's account if the partnership is still active. Otherwise, he must return the partner's share to him by any available means. It is not a condition to inform the partner of this; rather, it is sufficient to return his right and repent. It is not permissible to give the money to anyone other than its owner.