can you help me to upgrade my Macbook 13-inch, Aluminum, Late 2008

Upgrade how? OS? Hardware? Software? What are the current specs (memory, hard drive/SSD) & macOS version? You can get this information by clicking the Apple menu and selecting "About This Mac".

Writing an effective Apple Support Commun… - Apple Community

You do not say what OS you are running. The late 2008 Aluminum MacBook can only go as high as El Capitan.

How to get old versions of macOS - Apple Support