Hi there, our company is in China and we'd like to invite a guest from Finland to China to attend our meeting. I checked online and they said we Letter of invitation from a company or institution in China, or a Visa Notification Form issued by an authorized unit in China will be needed for F visa application. Could you please advise if the Letter of invitation from our company is enough? or we must get a Notification form from government? And do they have any requirements on Letter of invitation from company? Thanks for your help.