A spaceship capable of interplanetary flight but not interstellar flight is a DropShip.
A spaceship capable of interstellar flight is a JumpShip.
We own a DropShip (the Leopard-class Hysteria) and later a larger Argo-class Argo. We do not ever own a JumpShip.
The reason for this is that JumpShips are rare (depending on when you joined the BT community they are either rarer than hen's teeth - only about 2,000 across the entirety of the Inner Sphere - or just rare, perhaps ten or even a hundred times the old number), expensive, and utterly indispensable for interstellar civilization, since they are the only means to travel between stars. As such they were (of course...) priority targets during the First and Second Succession Wars, and off-limits as military targets for the Third and Fourth Succession Wars.
JumpShips are designed for one thing and one thing only: Faster-Than-Light travel between star systems, carrying a load of DropShips with them. They carry no cargo themselves, that's all carried by the DropShips. They are generally unarmed (except for some point defences against meteorites and other debris) and unarmored, and have to spend about a week practically immobile with a kilometers-wide solar sail deployed to recharge the KF drive.
DropShips on the other hand come in all shapes and sizes, and are designed for a multitude of missions; from dropping a lance of 'Mechs to landing a 'Mech regiment, from small tramp traders to massive cargo haulers, from spy ships to research bases like the Argo.
So how it works is basically that you check if there's a JumpShip going to wherever you're going (or one that can be paid to go there), then you spend about a week travelling in your DropShip from whatever planet you're leaving to the JumpShip that's sitting recharging its FTL drive at (one of) the star system's jump points. You dock with the JumpShip at a special KF docking collar that will extend the JumpShip's KF field to envelop your ship as well (practically making your DropShip a part of the JumpShip for the duration). Then, when the KF drive is sufficiently charged, the JumpShip jumps. In an instant you leave the system you're in and materialize in the system you're travelling to. The JumpShip unfurls its solar sail and starts the week-long job of recharging its drive, while you undock and spend about a week travelling to whatever planet you're bound for.
And that's it, in an abbreviated form. Two weeks, give or take, between any two planets within range of a JumpShips drive makes the galaxy a smaller place, but with the limited range of the KF drive's jumps, it still would take over a year to travel from one end of the Inner Sphere to the other.