do i need the receipt to fixing my phone in China?

You will have no problem in getting your device fixed, as this is accidental damage, which can be serviced by any ARS or Authorised Service Provider, the only question being if they have your specific part in stock. A wise step would be contacting the support line in China, using the information here - Contact Apple for support and service - Apple Support so they can arrange an appointment for you, so that you can avoid possible queues.

The Apple Limited Warranty covers the device regardless of the country of purchase. The only restrictions are when it comes to keyboards and other as such which might have regional settings or layouts. In either of the cases (accidental or manufacturing issue) the Apple Store in China will be able to provide support. It is true that when it comes to the second possibility, the customer might need to present a Proof of Purchase, in case the device was not purchased from an Apple Store. That is why I suggested contacting the support line before hand, to make sure she has all the details.

Apple One (1) Year Limited Warranty – Accessory - For Apple and Beats Branded Products Only.

radu369 wrote:

The Apple Limited Warranty covers the device regardless of the country of purchase. The only restrictions are when it comes to keyboards and other as such which might have regional settings or layouts. In either of the cases (accidental or manufacturing issue) the Apple Store in China will be able to provide support. It is true that when it comes to the second possibility, the customer might need to present a Proof of Purchase, in case the device was not purchased from an Apple Store. That is why I suggested contacting the support line before hand, to make sure she has all the details.

Apple One (1) Year Limited Warranty – Accessory - For Apple and Beats Branded Products Only.

Those terms don’t apply to iPhones (and cellular iPads). There are specific iPhone terms. This is for iPhones sold after August 26, 2016 in the United States:

Apple One (1) Year Limited Warranty

IMPORTANT RESTRICTION FOR iPHONE, iPAD AND APPLE TV SERVICE.

Apple may restrict warranty service for iPhone, iPad and Apple TV to the country where Apple or its Authorized Distributors originally sold the device.

It might be worth a try anyways, but there’s no guarantee that they’ll do it. Part of it may be that Apple wants to discourage gray marketing.

The warranty does not cover screen damage unless it is a manufacturing fault. iPhones usually have to be returned to the country where they were first purchased for warranty or service.

In some countries, formal Apple stores may take a casual look at a problem but repairs can require parts that are not available other than in the original country..

You are very determined, aren't you. You must read the threads before posting; this is an iPhone post and iPhones are not covered by an international warranty. Which is why I suggested that some stores may only casually look at the phone.

We don't know that this IS accidental damage. The author wrote "there is a problem with the screen". That problem, from that description may be a manufacturing defect. Hence my caution.