Do not search for third-party websites offering "GarageBand for Catalina.dmg". Those are often fake or contain malware. Always use the official Mac App Store.
. This will install version 10.3.5, which is the final version for Catalina. Option 2: If You Have Never Downloaded It Garageband For Catalina 10.15.7 -FREE- Download
The most reliable and safest way to get GarageBand on an older OS is through your . Apple allows users to download "the last compatible version" of an app if they have owned it previously. Steps to Download: Open the App Store on your Catalina Mac. Do not search for third-party websites offering "GarageBand