Click toolbar button or press M the first time to add a marker at the playhead (current position) with no dialog.
Markers appear in the time ruler/track/row at the top of the Timeline.
A marker shows a tool tip with its name and time when you hover the mouse over it.
Click a marker to seek to it.
Click toolbar button or press M when the playhead is on the exact start time of a marker to open the Edit dialog where you can change the name, color, start, and end times.
A color change is remembered for all new markers until changed.
Right-click a marker to open its context menu to Edit or Delete a marker.
Press Ctrl+Shift+M when the playhead is on the exact start time of a marker to Delete it.
Drag a marker to move it.
Ctrl+drag (command on macOS) a marker to changes its duration (a marker with a duration longer than one
frame is also called a Range).
Export > From lists all Ranges.
Markers are saved to the project file.
Marker operations support Undo and Redo.
More New Stuff
Added support for multiple selected clips to the timeline Cut, Copy, Paste, Overwrite, and Append
(Copy exclusively uses the system clipboard in this mode and does not show in the Source player.)
Added a Mask: Chroma Key filter for convenience, for example secondary color correction.
Added help message boxes to the Mask: Simple Shape, Mask: From File, and Text: Rich filters.
Added Properties > Comments for color clips.
Changed Ctrl+Shift+V in Text: Simple to paste.
Changed the color of an alert vs. the proxy/preview-scaling status messages.
Increased the time for some messages, and added the ability to click a message to dismiss it.
Upgraded FFmpeg to version 4.4.1.
Fixed a CPU compatibility issue in some 21.09 versions leading to crashes on some systems:
v21.09.13 on all platforms & v21.09.20 on Windows.
Fixed export to MP4 or MOV may not give constant frame rate (broke in v21.09.20).
Fixed Properties > Speed with GoPro .LRV proxy file (broke in v21.09.20).
Shotcut is a free, open source, cross-platform video editor for Windows, Mac and Linux. Major features include support for a wide range of formats; no import required meaning native timeline editing; Blackmagic Design support for input and preview monitoring; and resolution support to 4k.