How is our Master Muhammad, peace and blessings be upon him, invoked, and why is he invoked in the Tashahhud?

It is recommended for a Muslim to supplicate for the Prophet (peace and blessings be upon him) with words that do not imply any deficiency concerning him. It has been narrated that he asked 'Umar (may Allah be pleased with him) to supplicate for him.

It is permissible to supplicate for him for mercy and forgiveness, based on the hadith of the Bedouin who supplicated for the Prophet (peace and blessings be upon him) for mercy and forgiveness. The Prophet (peace and blessings be upon him) did not object to the core of the supplication but rather to its specific allocation (of mercy to him and the Bedouin, and none else).

Sending blessings upon the Prophet (peace and blessings be upon him) is a supplication for Allah to praise him in the Highest Assembly. Allah has commanded it, and the Prophet (peace and blessings be upon him) encouraged its abundance due to the immense virtue it holds.