To create an application like zocdoc, what language should I use, how many persons and how much time should I need to develop it?

Based on your requirement to serve the size of your target audience the technology requirement would mostly vary based on individual perspective and the performance expectations within the efficient use of the financial budget available.

If you wish to develop a website, and apps for android and iOS then you would require a particular language for each of the apps such as Java and Kotlin for Android apps and Swift for iOS apps.

Back-end technology for a Healthcare Apps

Development Team for Healthcare app Development

1. Team Leader or Project Manager

2. UI/UX Development team

3. Android App Development Team

4. iOS App Development Team

5. Web Developer

6. Back-end Development Team

If your feature selection requires various panel development then the approximate total time of Healthcare app development would be 4000 hours.

For further information on the Development of Healthcare app like ZocDoc you should read the article - How to build an app/website like Zocdoc | Features, Cost, Timeline