You can easily create a RESTful JSON API using Laravel to serve you mobile application. Laravel provides API Resources to allow you define the structure for your responses. Authentication can be handled by Sanctum if needed. Other than that there is nothing especially different from any MVC application; you define Models, routes, and Controller actions (which return the Resources rather than Views) necessary to solve your business needs.
I have a project to develop an already existing website, which is developed in Laravel 8. This website is an online food ordering system that contains its data on food items and others in the MySQL database. Plz, Guide me about the best way to develop an app for that website. And can I use MySQL database for app data? Please help me and guide me about the best technology to use for both Apple(IOS) and android.
You can write API with Laravel Sanctum & Laravel Passport:
In Laravel documentation Laravel Sanctum suggested for mobile applications/ SPA with different Laravel Passport provides a full OAuth2 server implementation.
Laravel doc:
If your application absolutely needs to support OAuth2, then you should use Laravel Passport.
However, if you are attempting to authenticate a single-page application, mobile application, or issue API tokens, you should use Laravel Sanctum. Laravel Sanctum does not support OAuth2; however, it provides a much simpler API authentication development experience.