Fertilizer breaks down mulch and any organic matter in the soil. Fertilizer under the mulch is more efficient than having it on top.
If you want to speed up a compost pile, add fertilizer.

Having a good mulch, over time, will make the adding of fertilizer unnecessary in most cases. I have a fairly large garden and haven't used fertilizer in years. I use woodchips as a mulch and it acts as a fertilizer.

Granular fertilizer sprinkled on a mulch washes down through it. The reason to pull the mulch back would be to keep it away from the stems. Most feeder roots of well-established trees and shrubs are out at the edge of the foliage canopy and beyond. That is also where most of the mulch needs to be to have the most effect on soil conditions being experienced by the newest roots.

Fertilize when there is a strong indication of a need, such as a soil test report. Use a product that provides the particular nutrients found to be deficient. Do not repeatedly apply fertilizer ingredients not known to be required. Over-application and toxicity are possible. Excess phosphorus in particular may be fairly common in home gardens.