I’d like to know if this is possible, thank you
you can import midi files into your project with ‘import as tracks’
If you mean import your vocal melody as midi so SynthV will make a string of "La"s in the timing and pitch of the midi imported then, yes. If you mean as and instrumental track, no. That has to be an audio file.
All informations are in the online manual 
Kanru thought of everything
When Mac version will be available, I’ll do a tuto for learning Synthesizer V
But in the meantime, I’m waiting 
yes, but if the midi has lyric data, the lyrics won’t transfer, even though when a SynthV midi is exported, the lyrics data is there. (COUGH COUGH SYNTHESIZER V IS KIND OF A HYPOCRYTE COUGH COUGH)
Actually the lyrics do transfer, and if you set that track to a voice it will sing. But most midis with lyrics are not properly synced to the music, and there are generally overlapping notes, so the result is usually pretty bad with gaps etc.
Please be aware that this thread is 3 years old, and the problem being discussed above was with the original “R1”/“first-generation” software, which has been since discontinued.
Current functionality of SynthV Studio (aka “R2”) may differ as it is an entirely separate software product.