WordPress sandbox

Hi There,

I am helping a company with their wordpress site, I am new to wordpress and so I am learning a lot. The company wants to have a safe development environment where they can work on their site in a testing enviornment that is not using github or the developer using a local environment. I have a local environment to work on thee site but they want an environment that can be accessed remotely by anyone else too. They do not want to github either. Any help would be greatly appreciated!

Thanks!