Q.what type of shrub would i need for ground covering.
the ground is against a fence,approx 3ft x 30ft under a large conifer tree. I am no gardener yet just retired.
Growing under conifers is difficult. The massive root system makes it hard for a new planting to get established. Moisture is pulled from the soil into the conifer. If the conifers have only recently been planted, there is more hope. Also take into consideration that it is unwise to severe many roots to dig planting holes. I've attached 2 links. One is RHS - a good reference to bookmark. Not knowing how much sun the area gets and the size of these conifers, it isn't possible to make specific recommendations. The second link is an article of possible candidates for growing under conifers. Choose small starter plants and find an area between roots for the planting hole.
https://www.rhs.org.uk/advice/profile?PID=430
https://www.thespruce.com/grass-doesnt-grow-under-pine-trees-2152742