Electricity to my shed
UF can be run in conduit, but the size can be tricky. There isn't a chart that says a specific size. NEC Chapter 9, Table 1, Note 9 says:


(9) A multiconductor cable, optical fiber cable, or flexible cord of
two or more conductors shall be treated as a single conductor for
calculating percentage conduit or tubing fill area. For cables that
have elliptical cross sections, the cross-sectional area calculation
shall be based on using the major diameter of the ellipse as a circle
diameter.

And then calculate per the allowed fill of 53% for a single conductor. I think 3/4&quot; SCH40 PVC will work for 12/2 UF, but an inspector might require the math.
Then search NEC Table 300.5 for required cover over conduit in trench.

Yes you need a switch, it could be as simple as a snap (light) switch.

A single circuit (even a MWBC) doesn't require ground rods.

The NEC allows cables to be exposed, cables must be secured to maintain 1.25&quot; clearance from either faces of stud or nail plated. Additionally it requires protection where subject to &quot;Physical Damage&quot;. The NEC doesn't define that well, giving local AHJ's broad room to adopt ordinances or arbitrarily decide that in a shed is all susceptible to damage from garden tools.

15A duplex receptacles are rated as 20A devices, you don't need 20A configuration.

Other thoughts. I don't put UF in conduit, it's hard to pull and generally a PITA to work with. If you run conduit and THWN wires then for almost no more work you can run a 4 wire MWBC, and double your capacity decreasing the chances of tools tripping lights.