Tourist visa for 4 persons,

We are 4 Austrian (tirol) going to visit peking from 12.4.2019 to 21.4.2019. Do we have to apply all the visa in person or it can be done by post. How much does it cost. It's single entry, entering Peking and back. We are getting different amount, is there a family-friendly price. How to get application form. Would it be problems as I am traveling to peking on same date but on different flight due to reservation problem. Please advice . Thanks