Will this update prevent my use of my 32 bit apps on my mac pro?

If you are asking about the upgrade to Catalina, 32 bit apps will not run on your Mac after you upgrade.

32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support

Catalina will not run 32-bit apps. Also see: 32-bit app compatibility with macOS High Sierra 10.13.4 and later - Apple Support

Llib1914 wrote:

Will this update prevent my use of my 32 bit apps on my mac pro?

I am asked update my mac pro. Is this going to impair my using 32 bit apps on my laptop and/or iPhone 7?

What macOS to what macOS???

It is still true if you install Catalina your 32-bit apps will not work.