You can add a marker at any position in your project. When you create a marker, it can be rounded to the nearest quarter note, to the nearest bar, or not rounded.
You can use the Create Marker key commands to add markers during playback.
In Logic Pro, do one of the following:
In the Marker List: Choose Options > Create.
In any workspace: Use the Create Marker key command.
A marker is added at the playhead position (if the playhead is aligned with a bar) or at the next bar position (if the playhead is between two bars). If a marker already exists at a bar position (or up to a quarter note before or after it), no new marker is created.
The length of the marker automatically extends to the start point of the next marker, or to the end of the project or folder, if no ensuing markers exist.
In Logic Pro, do one of the following:
In the Marker List: Choose Options > Create Without Rounding.
In any workspace: Use the Create Marker without rounding key command.
In the Logic Pro Marker List, click the Add Marker button 
.
In the Logic Pro Marker List, click in the Marker List area with the Pencil tool, then enter a position in the Position field.
In Logic Pro, do one of the following:
In the Marker track: Click the word Marker, then choose Create Markers From Regions from the shortcut menu.
In any working area: Use the Create Marker by Regions key command.
Markers created in these ways are automatically assigned the names, bar position, length, and color of the regions they are derived from.
In Logic Pro, drag the cycle area to the Marker track.
