You will find options to add different types of objects in that menu,
starting with polygons under the Mesh group and others like cameras,
lights, and even Collection instances. Depending on the project in
Blender, you might need a particular type of object. To get started with
3D modeling, the most straightforward type to create and manage is a
Mesh object (Polygon).
At the Mesh group, you can create geometrical primitives such as:
Plane
Cube
Circle
UV Sphere (square faces)
ICO Sphere (triangular facer)
Cylinder
Cone
Torus
We can use those primitives as a starting point for several modeling
projects. A Cube can become a chair or a human-head depending on the
number of modifications applied to the object.
To create a model at the 3D Viewport, you must pick a location to create
the object by placing the 3D Cursor and pressing the SHIFT+A keys or
using the Add menu. For instance, we can add a new Cylinder to the
scene (Figure 2.2).