Since future SpaceX Starship is planned as long duration passenger spacecraft for multiplanetary transport will it have launch abort system? Also how is crew evacuation planned during interplanetary flights and how during ascent from Moon, Mars?
It will almost certainly be required to have one for the terrestrial portion. Consider that both SpaceX's Crew Dragon and Boeing's Starliner have been required to have an in-flight abort test. I can't see NASA (or the forthcoming Space Command) skipping out on what are considered standard safety systems now.
Also how is crew evacuation planned during interplanetary flights and how during ascent from Moon, Mars?
This part is a bit trickier. It's easy to demand one for systems we already have, but you're talking about launching, landing and then potentially using on Mars. To date, nobody has sent something to Mars and then had it lift off again. While it would be nice to have in-flight abort here as well, that may not be feasible. None of the Apollo lunar landers had in-flight abort either.