That’s why it’s called an MWE - the point is to only post code which illustrates your specific problem. In your case an MWE is:
julia> using Plots
julia> pie(["Y", "N"], [25, 75])
and one answer to annotating the plot is:
julia> annotate!([-0.25, 0.25], [-0.25, 0.25], ["75%", "25%"])