The final goal of all Yogic path is Samadhi; enlightenment or going beyond the mind and ego to connect with our true self.
Selfless service is Karma yoga. Without expecting any rewards and not accumulating any Karma. Yoga of action. And a great yogic path for those who are active, physical and energetic. One has to perform action with being attached the 'fruits'.
As quoted from the Bagavad Gita below:
tasmad asaktah satatam karyam karma samacara asakto hy acaran karma param apnoti purushah"
Therefore, without being attached to the results of activities, one should act as a matter of duty, for by working without attachment one attains the Supreme