įriendly NPCs do not attack bounties, unlike pirates. Players tend to prefer taking these missions and then continuing on their business the mission target will present itself then as an ambush, but with a good ship, pirates ambush the player anyway, and it saves a lot of time searching for the target. The bounty is always in one system, if you find them then leave the system you can go back at any time and they will still be there. Named pirates will always be within two systems of the planet offering the bounty, unless they are marauder bounties then it's up to three jumps away. (The editor assumes this opens up either at a certain combat rating, or after a certain amount of time has passed.)
Pirates always attack in the destination system, if not before. The description usually says which ones can get you fined. Other normal missions consist of carrying packages, taking other pilots missed rush deliveries, etc. Many are smuggling missions to the paradise worlds, if the republic scans you the fines are heavy.