Positions of chord symbols
By default, chord symbols are centered horizontally on the middle of the front notehead in the first voice column, at the rhythmic position to which they are attached.
The front notehead is the notehead on the correct side of the stem at that rhythmic position.
Their vertical position in full scores is determined by the staves above which they are set to appear and any chord symbol regions you have input. This also affects in which part layouts chord symbols appear.
Alignment of chord symbols relative to notes and chords
You can change whether chord symbol text is left-aligned above the notehead, center-aligned above the notehead, or right-aligned above the notehead, although right-aligned typically produces unclear results.
You can change the horizontal alignment of chord symbols by choosing an option for Horizontal alignment relative to note, chord or rest in the Position section of the Chord Symbols page in Engraving Options.
You can also override this for an individually selected chord symbol by activating Alignment in the Chord Symbols group of the Properties panel and selecting an option from the menu.
Alignment of chord symbols across the system
Chord symbols are aligned at the same vertical position across the width of the system by default. You can deactivate Align chord symbols across width of system in the Position section of the Chord Symbols page in Engraving Options if you want each chord symbol to be positioned above the staff independently.