As others have mentioned, the types of policies you need will depend on what your app does and, perhaps, what it doesn’t do. I think it is really important for you to seek the advice of a legal professional to help you determine what legal disclosures are necessary for your app; a lawyer would be able to give you specific guidance tailored for your app.
My companyprovides startups and small businesses with a cost-effective platform to secure legal services for all of their business needs. Our attorneys are pre-vetted, highly-trained and have solid legal experience, especially with tech startups. We offer a free consultation and no-obligation price quotes. Check us out; we’d love to help you with your business. Good luck!