CreateTestDrive.cs

public static void CreateTestDrive(TestDriveDetail testDrive, IOrganizationService crmService)
{
    var lead = new Microsoft.Xrm.Sdk.Entity(EntityName);
    //lead.Attributes
    lead.Attributes.Add(Field_Subject, $"Test Drive Request by {testDrive.CustomerName}");
    lead.Attributes.Add(Field_FirstName, testDrive.CustomerName);
    lead.Attributes.Add(Field_Description, $@"Test drive request summary:
                            {Environment.NewLine}Car Make: {testDrive.CarMake},
                            {Environment.NewLine}Car Model: {testDrive.CarModel},
                            {Environment.NewLine}Requested Time: {testDrive.RequestedTime},
                            {Environment.NewLine}Customer Name: {testDrive.CustomerName},
                            {Environment.NewLine}Phone Number: {testDrive.PhoneNumber}");            

    crmService.Create(lead);
}