Most of the time, hiring an electrician is the smart move.
If you are simply swapping out an old light for a new pendant and there is already a properly installed ceiling box, some homeowners feel comfortable handling it themselves. Turn off the breaker, follow the instructions, connect the wires carefully.
But electricity is not something to guess your way through.
An electrician will make sure the junction box is secure and rated for the weight of the fixture. They will check that the wiring is up to code and that the connections are tight and safe. That matters more than people think.
If you are adding a pendant where there was no light before, the answer is almost always yes. Running new wiring through ceilings or walls is more involved than it sounds. There are structural considerations and local code requirements to follow.
There is also placement. Getting the height right over an island or table can take a bit of measuring and adjustment. A professional can help make sure it lands where it should.
Could you do it yourself? In some cases, maybe.
Should you, if you are unsure? Probably not.
Good lighting should feel easy. The wiring behind it should be solid.