See section 11.6.2 for points in the plane.
With the 3-d geometry screen in point mode, a click on a point with the left mouse button will choose that point. Points chosen this way are automatically named, first with A, then B, etc.
Alternatively, the point command chooses a point, where the
point (a,b,c) is specified by either the three coordinates
a,b,c or a list [a,b,c] of the coordinates. Many
commands which takes points as arguments can either take them as
point(a,b,c) or the list of coordinates [a,b,c].
Input:
or:
Output:
(The marker used to indicate the point can be changed; see section 11.3.2.)