Consultant going to Inspect goods ordered.

Hello,

I am a business consultant who ordered and paid for UHMWPE Pipes from Shandong. The order is ready and needs to be inspected for shipping. The company has scanned and sent to my email a letter of invitation. Will this suffice for the invitation letter, or do they need to send me the original by DHL? I am willing to bring in my laptop to confirm all the correspondence exchanged over 2 months. Secondly, I am interested in checking on some other manufacturers of various products around Shandong. Will I need special permission for this? My maximum stay will be 3 days before heading to Malaysia. Thank you.