Python 3 isn't installed in macOS by default but it is added if you install the Xcode Developer Tools. You can of course install your own version of Python 3 without an issue.
Apple has made no announcement regarding the future of Python 3.
The version of Python 3 installed via Xcode or Command Line Tools (CLT) can probably not be removed specifically, unless you delete Xcode or the CLT as a whole. However, you can install Python 3 yourself and it can coexist with Apple’s version. For example, the installer package from python.org will install the binaries or symlinks thereof in /usr/local/bin. That location is already in $PATH.