64 app intel

No App exists to do that, nor is it even possible to do it. The Intel Processor in a Mac is already 64bit. There's nothing you need to do to it.

The message you are seeing is in relation to the applications you are running on your Mac, not the processor.

32 Bit Apps will cease to run on the next version of macOS named Catalina. Its those apps you need to update. Developers should provide updates to those Apps to be 64 bit compliant.

If you don't update to Catalina when its released, then you don't need to do anything.

Your Mac is already 64-bit and has been for years. So are most Apple apps. The only apps that need to be updated are third party 32-bit apps and only if and when you install Catalina, the next Mac OS.

You are not understanding the 32 bit to 64 bit upgrade requirement. Your 32 bit third party apps will need to be upgraded if you upgrade your operating system beyond Mojave. To upgrade these apps contact their respective developers.