learning the chords

[johand]

I gave "FlyMe to theMoon" a try yesterday evening. Biggest problem where finding the 7th chords, and how to finger them. Maybe I can gather a few tips here.
Are there any good apps to quickly look up chords and its inversions? Or any other ways to learn the chords and find them easily. Maybe it's not a question for an app-forum, but as all people are musicians post here...
How to see at what octave do I have to take the chord?
Another question: How do I see from the letters on a leadsheet if I have to play the plain chord or an inversion - or may it is always be allowed to have easier fingering?


edit:
OK, I found the "display chords - 1 hand" function in iReal Pro, but sometimes he chooses to play an inversion, and sometimes the root chord. Nevertheless. The letter in the leadsheet always indicate the root chord.