Hi there,
There’s quite to do there with getting a test site setup for people to access outside.
1.) First, you would have to install a server software on your computer; https://www.mamp.info/en/
2.) Install and configure WordPress under the directory that the ^^ above server can access
3.) If you can go to localhost and see WordPress, you did good.
4.) You need a domain or your ISP IP address has to be forwarding to your local computer IP through your router. You could also use service https://www.noip.com/ … which will use your ISP IP that probably changes a lot or every time you reboot your system. You might still forward the right ports and IPs within your router.
5.) After all said and done, give your friends or people the IP address or the domain that NOIP.com gives you. They should be able to access your WordPress site.
The above of course is a quick run down of what steps to take. It all depends on your home / office network setup.
Hope that helps ??