In version 1.4 and newer, Cartographica allows direct manipulation of point locations through the Point Data window when you are adding a feature. When using 1.4 and newer:
Generally, if I have more than a couple of points to put in, I open a text editor and type them in (or copy and paste), in the format:
X,Y,Name
<longitude1>,<latitude1>,<name1>
<longitude2>,<latitude2>,<name2>
and then use File > Import Table data and map the 2 coordinates columns to X and Y.
Prior versions of Cartographica do not have a streamlined way to create a new point using X and Y coordinates.
The un-streamlined way goes basically like this: