Under the Apple Menu:
- Click Software Update
- A message will appear, Checking for Updates
- A message will appear, Software updates are available for your computer. Do you want to install them now?
- Click install
Each browser is different but for Firefox and Chrome:
- Go to the Firefox/Chrome menu
- Click About Firefox/Chrome
- You will see a message that the browser is up-to-date or a link to click to update to the latest version.