What are the best deeds that can be dedicated to the deceased according to the Qur’an and Sunnah, and does the deceased feel this dedication and know who presented it to them, and does that count in their scale of good deeds, and does the one who presents it receive a reward for that?

The best acts of obedience to dedicate their reward to your mother after her death are charity (sadaqah) and supplication (du'a), as scholars unanimously agree that their reward reaches the deceased, while they differ on others. The best charity is providing water. Your mother will benefit from their reward, and it will be added to her scale of good deeds. She will feel this dedication and know who dedicated it to her, as mentioned by Ibn al-Qayyim in his book, "Al-Ruh" (The Soul). As for your dedication, there are two opinions among scholars: some believe you will receive a reward, while others believe you will not receive a reward, but you will be recompensed for your dutifulness and kindness.