Hey Reza! Andy from Segment here.
If you are using Segment from the browser, make sure you add our JS snippet (instructions here):
Then, in order to '.identify()' a user:
And to send a '.track()' call:
These would map to Mixpanel's 'window.mixpanel.people.set' and 'window.mixpanel.track'.
More details here:
If you have more questions, please email email@example.com