I am creating inv from 2018, and i get this msg...."Pls select a transaction date that comes after the date you started tracking the qty on hand of these inventory items

You'll get this prompt if the date on the transaction comes before the "Ad of date" of the inventory item, @fayorseycyril.

You can edit the item's starting value date by following the steps below:

1. Go to Gear, then Products and services.
2. Locate the item in question, then Edit.
3. Click the Starting value link, select Continue when prompted.
4. Change the As of date of the item.
5. Hit Save and close. 

Please see this article for more information about changing product and service item types in QuickBooks Online. I'll also share our page about income and expenses for more tips and recommendations.

That'll do it. Know that you're always welcome to swing by anytime if you have other questions or concerns. I'm always here to lend a hand. Thanks for visiting us today and have a good one.