Face amount, also known as par value, is the amount that the bondholder will receive at maturity date assuming the issuer of the bond does not default. On the other hand, the settlement amount is the amount that the bondholder pays or receives for the face value; it accounts for the accrued interest, taxes and applicable fees.
When a security is traded at a discount (YTM > Coupon rate), the settlement amount may be less than the face amount. On the other hand, when a security is traded at a premium, (YTM < Coupon rate), the settlement amount is greater than the face amount.