F visa gov invitation letter issue

I am working in Riyadh. I need to go for a business trip to Shanghai. I checked with my company office in china for the gov invitation letter for "F" Visa, but they said china government stop the invitation letter for pakistan passport since 2 months. Please confirm is this was the case and it is still valid?

Also let me know can I apply for tourist visa and do I need invitation letter for tourist visa and how to apply for this?

Thank you...