AddObjectScript.py

import bpy

class TestPanel(bpy.types.Panel):
    bl_label="Test Panel"
    bl_idname="PT_TestPanel"
    bl_space_type='VIEW_3D'
    bl_region_type='UI'
    bl_category='My 1st Addon'
    
    def draw(self,context):
        layout=self.layout
        
        row=layout.row()
        row.label(text="Add an object", icon='CUBE')
        row=layout.row()
        row.operator("mesh.primitive_cube_add", icon='CUBE')
        row=layout.row()
        row.operator("mesh.primitive_uv_sphere_add", icon='SPHERE')
        row=layout.row()
        row.operator("object.text_add", text="Font Button")
        
        
        
def register():
    bpy.utils.register_class(TestPanel)
    
def unregister():
    bpy.utils.unregister_class(TestPanel)
    
if __name__=="__main__":
    register()