The OnePlus 8 series went up for pre-order on April 15 and the devices are scheduled to launch officially starting next week or by the end of April, depending on where you live. However, many customers who pre-ordered the OnePlus 8 or OnePlus 8 Pro have already got the phone delivered to them ahead of its release date.
The OnePlus 8 shipping thread over at OnePlus' forums is filled with customers whose packages are out for delivery or who have already received their phones. Customers are getting the OnePlus 8 or 8 Pro depending on their order along with the Warp Charge 30 wireless charging dock and the Bullets Wireless Z earphones. OnePlus was bundling the latter two items for free a part of the pre-order package for the OnePlus 8 Pro when it first started accepting pre-orders for it.
If you pre-ordered the OnePlus 8, you should check your order status to see if your package has been shipped out or not. Delivery will depend on where you live and there can be a slight delay due to the COVID-19 pandemic which has crippled global supply-chain and forced people to work from home across the globe.