For a typical TRS (tip, ring, sleeve, referring to the tip of the plug, the ring inbetween the tip and the sleeve, and the long bit which is the sleeve) plug, the pinout is of similar design, with
the shortest tab, connecting to the center, being the tip
the middle length tab, connecting to a ring in the middle, being the ring
the longest tab, with or without the crimp and essentially connected to the bare metal that goes all the way around, being the sleeve.
TRRS (the one with 4 pins that some are referring to in the comments) simply adds a secondary ring, with an accompanying tab across from the sleeve tab.