public void ConfigureServices(IServiceCollection services)
{
    ...
    var config = new TypeAdapterConfig();
    // Or
    // var config = TypeAdapterConfig.GlobalSettings;
    services.AddSingleton(config);
    services.AddScoped<IMapper, ServiceMapper>();
    ...
}

config.NewConfig<Poco, Dto>()
    .Map(dest => dest.Name, src => MapContext.Current.GetService<INameFormatter>().Format(src.Name));

public class FooService {
    private readonly IMapper _mapper;
    public FooService(IMapper mapper) {
        _mapper = mapper;
    }
    public void DoSomething(Poco poco) {
        var dto = _mapper.Map<Dto>(poco);
        ...
    }
}