"Extension" for Chinese visa actually means if your current visa is expiring, you have to apply for a new visa.

The relative ease or the amount of documentation required for obtaining a F visa would depend on your nationality as defined by the passport you are holding, whether you are applying to the Chinese diplomatic mission in your home country or if you are in China, the visa issuing authority in China or if you are in a third country, the nearest Chinese diplomatic mission.

For a F visa, the most crucial documentary requirement is: A formal invitation letter from a Chinese business firm or institution; the business licence or incorporation documentation of your hosting organisation in China. Plus a duly completed ad signed standard application form and passport photos, of course. And depending on your nationality and where you apply, additional documentation may be required, such as: your business licence; a guarantor letter; the "commercial entity code recording sheet" of your hosting organisation; evidence of financial means to cover the trip in the forms of bank statement with sufficient funds or cash or bank draft and so on, confirmed airline booking to and from China, hotel booking voucher for the visiting period or documentation for other forms of accommodation arrangement while in China. Moreover citizens of certain south Asian countries can only apply for business visas in their home country. The first course of action might be advisable for you to check with the local Chinese diplomatic mission in your home country.

If you encounter difficulties and require assistance you may contact me direct, I advise travellers to China for business or leisure on matters like shopping, sourcing, business introduction, administrative and official formalities, etc in the pan_Pearl River Delta region around Guangzhou and beyond. My contact details are: 163.com|georgeee Tel: ( 86)13431078131. Cheers