This groundcover does not demand a lot of fertilizer. Do not overfertilize as this can make the pachysandra susceptible to sucking insects such as scale.
It would be okay to spread a thin layer of compost around the base of the plants.
Be sure to remove any fallen debris and clean up of old leaves etc. to help reduce and prevent fungal issues.
Test your soil before applying any fertilizers. Results will give pH and nutrient deficiencies. http://extension.umd.edu/hgic/soils/soil-testing