Gloria, one of the benefits to applying mulch is that it can help to prevent the germination of weed seeds. But, it will work the same for desirable seeds as you guessed. You can't cover seeds with mulch and expect them to sprout.

Yes, you can cover seeds with mulch and expect them to grow, and mulch will not stop weeds from sprouting.

There are two separate things going on: sprouting and growing, and they are separate processes. Sprouting will not occur if the seeds have dried out after sowing. An airy sort of mulch will shield from the drying wind and the hot Sun but let light and air in. If a leaf can see light, it'll grow to it.

A thick layer of heavy mulch like pine bark, gravel, or tree chipper run will prevent growth by smothering after sprouting.

The problem is that no one has defined "mulch" here. It can mean anything from a six inch layer of ground up truck tires to a sprinkling of pine needles.

There is a limited amount of nutrients/energy stored within the seed, only enough to get the cotyledons to the surface and into light where they can begin to make their own 'food'. Cover it too deeply with soil or mulch and that energy is expended before the seedling begins to grow - it dies.