Can I record without an external interface on the Maschine mk3
I don't have an MK3 but looking at it I would have an educated guess at YES
Seems you have these input channels which should appear as selectable inputs in Maschine audio input section.
Line In for any hardware device you wanna plug in and record
Mic In for plugging in a mic I guess and recording your killer vocal track
Seems this is exactly what these inputs would be for since the MK3 has an on-board audio interface.
Duplicated post. Please refer to this post instead: How do I connect my mic with Maschine MK3 in Logic Pro?