delete apps MacBook air

If the app was downloaded from the App Store, see the "Uninstall apps" section of View and manage purchased apps in the App Store on Mac - Apple Support

If it wasn't downloaded from the App Store, see the "Uninstall apps" section of Install and uninstall apps from the internet or a disc on Mac - Apple Support

Also, if the app has a subscription, see If you want to cancel a subscription from Apple - Apple Support

Just to add to the (very complete) advice provided by FoxFifth...

You can't delete apps that were installed as part of MacOS. Examples of these apps would include:

• Finder
• App Store
• Mail
• Calendar
• Notes
• Reminders
• ...and several others