Many consider that even the apps are already included (or at least I have been asked) because nowadays one sees platforms with mobile apps all in one but the truth is that in many cases it is still a completely separate technology from the platforms and are connected via APIs and other technologies, even are other programming languages!
My recommendation is to start with the platform/website and then create the mobile App or vice versa unless the budget is not a problem.
These platforms that help you to create your project in a more visual way, usually include a function to also create an APP or even create the APP directly without a website or anything! it is a good solution worth checking out. and more if it is for an MVP! Here are some of the tools that can help you!
Programmed Mobile App
With one or more programmers you can create the mobile application you want, there are different types of technology to create them and it also depends if you only want it for Android or iPhone, as each has its own native programming language to create the application as compatible as possible, but there are programming languages like React Native and Flutter, that with the same code project) can be developed for both operating systems. I think these last two options would be ideal for you, but it will depend on your requirements, try to find programmers with these profiles, a good one should also help you to indicate whether it is possible or not to do what you need.
Here it depends on your requirements and the research of the programmer or programmers that best suit you, you can search comfortably on Fiverr or Upwork among other platforms or agencies to hire these services. Also, don’t forget that I am here to help you in the process and I even have a partner team that so far has not disappointed me by creating quality products in good time. In general, I would review with you the requirements and we would look for a way to develop the platform you want so much in an efficient and quality way, trust that there are always things that one skip and several heads think better than one.