How to check if your Mac’s software is 32- or 64-bit

MacOS 10.14 Mojave, the version of the Mac operating system before the new macOS Catalina, is the last version that supports 32-bit software. With Catalina, only 64-bit software will be supported.Catalina is here and if you decide to upgrade to the new macOS, you need to do a bit more than usual to prepare your Mac. You need to make sure your apps are 64-bit versions. If your app is a 32-bit version, it will not work. Apple
Apple actually started to warn people about the change with macOS