Set up a local development environment. Some popular options:
1) MAMP/XAMP/WAMP – run an Apache server environment with PHP and MySQL. Apache, MySQL, and PHP come pre-configured. Put your websites into the htdocs folder, turn on the WAMP/XAMP/MAMP server, browse to the server’s URL and you can view your site. This is all local to your machine.
2) VVV – https://github.com/Varying-Vagrant-Vagrants/VVV – run a virtualized server using VirtualBox (https://www.virtualbox.org/wiki/Downloads) on your local machine.
3) Bitnami Stacks: https://bitnami.com/stacks
Allows you to run the server on your local machine with pre-configured “stacks”. However this is pretty much turning your machine into the server so you’ll want to be careful and run this behind a good firewall and other network security. But it can be as local as you’d like. This option might work well if you have an old computer around that you’re okay running as a server on your local network.
4) Or there’s ServerPress (https://serverpress.com/) which is an application specifically designed for working on WordPress sites locally.