Star Trek: 10 Devices That Every Starfleet Ship Has
6. Impulse Engines
Warp travel (which will be explained more later) is fundamentally different from how a Federation ship moves usually. While travelling slower than light, the ship uses it's impulse engines which are essentially fusion rockets. They generate a nuclear plasma exhaust that propels the ship forward.
The ship also has smaller thruster engines facing all directions to control inertia because an object in space that moves in one direction will continue to move that direction at the same speed forever unless acted on by a force.
This technology hasn't changed much at all from Archer's Enterprise in the 22nd century all the way to Star Trek Picard and beyond, and this is because there is a limit to how fast impulse engines can even be. Because of the laws of relativity, no object can move faster than light without using a warp drive or other space-bending method. This is why, while impulse engines may get more maneuverable over time, they will always remain sub-lightspeed.