Long pressing the Chords Tab will unfolde three menus. Then are Chords Reverse Search, Chords by note andf Chords by keys. Choose Search to enter Chords Reverse Search.
If you find some fingering sounds great but don’t know its name, reverse search is designed to find out the chord name of the corresponding fingering.
If you tap some notes on the Fret board, the title bar on the top of the screen  will provide the possible chords name, while the white sub-title shows the corresponding notes.
Tap the reset button  to reset the search state.
Tap the note on the fret board again to mute the string. For example, tap the E note will mute this string. Once the string is muted, you’ll see the red “x” button on the fret board.
Sometimes there will be many chord search results for a certain fingering. Press the down arrow  on the top right to show more possible chords.
Learn more information in Wikipedia: