To Taper One or More Faces on a Solid

Select the Taper Face tool.
In the Draft Angle field, type the required angle for the taper.
Select the solid.
The solid is highlighted.
Select the face to taper.
The selected face is highlighted.
(Optional) Select further faces to taper using <ctrl+data points>.
Accept the selected face(s) with a data point.
This also defines the vector start point for the taper.
Define (with a data point) the vector end point for the taper.
The vector start and end points define the direction of the taper, onto which the draft angle is applied. On defining the vector end point, the taper is constructed.

Selecting a face with Add Smooth Faces off, left. The result, right.

Selecting a face with Add Smooth Faces on, left. The result, right.