Yes, you can create a single invoice in the New Invoice page. This page just gives you the option of creating either a single invoice or multiple invoices.
The two videos below shows how to create an invoice and how to create a batch.
If you create a single invoice, you will be taken to the single invoice in the Invoice Details page.
If you create multiple invoices, it will be listed as an invoice batch in the and you will be taken to the Invoice Batch screen and you see the list of all the invoices that were created in that batch.