The usual way of getting between the stars is through the use of a Jump Drive. These are capable of moving a ship across multiple parsecs in the period of a week. A jump always lasts about a week, regardless of the distance. More powerful/advanced drives can travel further distances in that week, but they can't take less time to move a shorter distance.

The most advanced jump drives, at TL 16+, have a range of 6 parsecs. The basic jump drive, introduced at TL 10, could manage 1 parsec. The TL 10 drive was highly experimental, and took up most of a ship's mass.

The rule of thumb is that a jump drive can't initiate a jump, or end a jump, within 100 diameters of a planet or star. More accurately, it is based on the strength of the gravitational field, so dense objects such as white dwarfs or neutron stars have a jump mask which is much larger than 100 diameters.

It also means that low density worlds, such as gas giants, have a smaller jump mask than their diameter would suggest.

Jumping closer to a planet or star is possible, but dangerous. The higher the TL of the drive, and the quality of the astrogator and computer systems of the ship, the closer to the planet it is possible to get. This difference though is marginal.

The jump mask around an object also prevents jumping into any point which is within the shadow of that mask. So you can't jump to any point directly on the other side of a planet or star, you need to first move to the side.

This means that worlds will have times when it isn't possible to jump directly to them from another system, since they will be in the jump shadow of the star. When this happens, it is necessary to jump to a place in the orbit to the edge of the star's shadow, and then manoeuvre to the planet.