Yes, you can run PyTorch (frequently referred to as "Torch") on your phone, but it is not a simple "one-click" app download from an app store. Instead, you can use specialized frameworks designed for mobile performance or third-party apps that provide a Python environment.
There is no official "PyTorch" app in the Apple App Store or Google Play Store that allows you to build models from scratch on your phone. However, you can use mobile-friendly versions and environments: An Overview of the PyTorch Mobile Demo Apps can i download torch on my phone