Tukar serbis to China Mainland to access Apple store China, but you'll have to change all your address for billing to China. Well, I use 123-456 as postcode and phone number 010101011 sorta to kaotim the address, but after download, you also find it hard to login or open new ID for douyin coz they need you to tied up with a +86 phone number.

Casual use, I think NVM. (Know it coz I just done it for my wife Iphone yesterday afternoon)