Difference Between Documents checkable in tcode FB03 / MIR4

Hi,

I am wondering about the difference between the two supplier invoices.

1. the one you can post through tcode FB60 (standard number range 10XXXXXXX), which you may check in tcode FB03

2. the one you can post from the App "Create Supplier Invoice" (standard number range 51XXXXXXXX), which you may check in tcode MIR4

I guess No.1 is in FI, No.2 is in MM, though both are called Supplier Invoice. Automatic Payment will not catch up the document of No.2, starting to wonder which is what.