Hi EZBZ,
Yes, in terms of native functionality, Dynamics 365 Business Central will not auto-generate a barcode from a value you enter in another field.
That said, you can manually add barcode information for an item by going to an Item's card page, clicking on Cross References in the ribbon. Here, in the Cross-Reference Type field, select Bar Code, and in the Cross-Reference No. field, type in the barcode information.
I am sure that we will soon have one or more apps in AppSource to make barcoding more seamless in Business Central, just like we do in the on-prem edition of the solution (Dynamics NAV).
I hope this helps. If my response has answered your question, please verify by clicking Yes next to "Did this answer your question?"