Add Some Padding To Create Space Between The Elements?

i have this string, i want to add some padding to create space between the elements. here is my code

StringBuilder sb = new StringBuilder();
for (int i = 0; i != confirmedOrder.Items.Length; ++i)
{
sb.AppendLine(
string.Format(
"{0} {1} {2} {3} <br />",
confirmedOrder.Items[i].ItemNumber,
confirmedOrder.Items[i].ProductTitle ,
confirmedOrder.Items[i].Size,
confirmedOrder.Items[i].Price.ToString("c")
)
);
}

as you can see i want to remove the and include some padding so the item details have some space between them.