Solution

MapInfo Professional has a number of editing modes which may assist you in digitizing.

To toggle using these functions when digitizing, use the following keys -

S = Snap
T = Autotrace
N = Autonode e.g. a free hand polyline

Also note that any closed polyline can be converted to a polygon, by selecting it and using Objects>Convert to Region, and vice versa using Objects>Convert to Polylines.