
If you'd like, you can set up the system so that unposted and posted invoices share the same number. This can be done by assigning the same number series to both invoices and posted invoices. Currently, if you check the Sales & Receivables Setup page and the Purchases & Payables Setup page, you'll see that invoices and posted invoices have different number series.
The reason you might prefer different numbers is that if you use the same number series, when an unposted invoice is deleted, the system automatically creates a blank posted invoice with that number to reserve it. By using separate numbers, this doesn't happen. Additionally, some companies use both orders and invoices to post invoices, making it more practical for orders and invoices to have separate numbers from posted invoices. Ultimately, it's a matter of preference, and the system can accommodate either setup.
Valentin Castravet
Work: Zander ERP Services
Blog: Dynamics 365 Business Central Insights
LinkedIn: www.linkedin.com/in/valentin-c-0500a247/