All modern apps are 64 bit and Apple dropped support for 32 bit with macOS 10.15, Catalina. If you are running an older OS and considering updating to 10.15 or newer, or you are buying a new computer which requires a newer OS, you might find this tip useful to get a list of all 32 bit apps on your machine, so you know what you will which you need new versions of.
Go to System Information (Apple > About this Mac, then click System Report). Click Applications in the Software section. Wait a few seconds for the list to be created. All apps shown, including 32/64 bit status. You can sort on the 32/64 column to see all the older apps together.
Note: This assumes you are running an older OS, because there is very little point in doing this for a newer OS which cannot run 32 bit apps anyway.