Extend and close curve points in Blender

Prerequisites

• Blender v2.93
• macOS Big Sur v11.6

Steps

In the 1st, adding aCurveobject.
Click Add > Curve > Bezier in Object Mode.

Blender created Bezier curve object.

Click point.

Click Control Points > Set Handle Type > Vector.

Move point.

Extend

Now let’s close the curve. Select points.

Click Control Points > Make Segment to close a curve.

Result it.