The minimum hardware requirements for using Scratch online are detailed in the FAQ on the Scratch website.

The offline version of Scratch 3 is called Scratch Desktop, and it runs on Window 10, macOS 10.13, or newer Windows or Apple operating systems. Older versions of Scratch are still available to install and run on older operating systems. Note that we recommend upgrading to Scratch 3 as soon as you can, so that you can make use of the latest features and projects.