Apple Logic Pro X - Manual (Page 668)

Chapter 20 View and edit music notation 668
Set the finger number for a fingering dot
m Control-click a dot, then choose a number between 0 and 5.
Add an optional fingering dot
Do one of the following:
m Option-click a string to create an optional dot. If another real dot exists on the same string, the
real dot remains.
m Option-click an existing dot to change it to an optional dot. An empty string is shown as a result.