Getting power to a building that isn't attached to the house almost always means going underground. The electrician handles the wiring and the connections; the conduit is the protected pathway that wire runs through, and it has to be right before the ground closes over it.
The route comes first. Shorter is cheaper, but the straightest line isn't always the best one if it crosses a septic field, a water line, or a big tree's roots. We plan around those, and around the private lines that 811 won't mark.
Depth matters too. Buried electrical conduit has minimum cover requirements set by code, and they vary with the conduit type and where it runs, such as under a driveway versus open lawn. We use PVC conduit sized for the wire your electrician specifies, with long sweeps at each end so the pull is smooth and a pull string left inside.
Before backfilling, warning tape goes into the trench above the conduit so anyone digging later knows what's below. Then the soil is compacted in layers and the surface restored. Most homeowners are surprised how little trace is left once the grass comes back.
One tip: if you're planning a shop, garage, or charger, run a spare conduit while the trench is open. Adding fiber, low-voltage wiring, or a second circuit later costs a fraction of digging a new trench.