how to delete old back up files in Itunes. My labtop is full?

To find a specific backup:

1. On a Mac with macOS Catalina 10.15 or later, open the Finder. On a Mac with macOS Mojave 10.14 or earlier, or on a PC, open iTunes. Click your device.
2. In the Finder, under the General tab, click Manage Backups to see a list of your backups. From here, you can right-click on the backup that you want, then choose Show in Finder, or you can select Delete or Archive. In iTunes, choose Preferences, then click Devices. From here, you can right-click on the backup that you want, then choose Show in Finder, or you can select Delete or Archive.
3. 
4. Click OK when you’ve finished.

Backups on your Mac

To find a list of your backups:

1. Click the magnifier icon  in the menu bar.
2. Type or copy and paste this: ~/Library/Application Support/MobileSync/Backup/
3. Press Return.

Backup Location

For Windows PC:- \Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup\

For Mac:- ~/Library/Application Support/MobileSync/Backup/