I don’t know the best way to explain it. But for example, there’s a code editor app I use on my phone that is connected to one of my GitHub repos. So the repo is essentially represented as a folder on the app, and I can access all the files there.
So if I edit a text file “example.txt” in the master branch, and then save it on the code editor app; it automatically commits and pushes the changes to the repo. And it also continuously is updated when the repo is changed by through other means. So if I decide to edit the same “example.txt” file within my repo on my PC, the changes will also be shown on my code editor app. It’s essentially all in-sync. If you want, I can show you the exact code editor app on the Google Play Store