The Schematic Edit Ribbon tab is shown below.

The PCB Edit Ribbon tab is shown below.

Edit

Undo the last action.

Redo the last undo.

Cut the selected objects to the clipboard.

Delete the selected objects. They are NOT placed on the clipboard and so cannot be pasted.

Copy the selected objects to the clipboard.

Paste the clipboard. Available formats are text, images and DEX objects.

Clear the current sheet. All objects are deleted. They are NOT placed on the clipboard and so cannot be pasted.

Select

Set viewport mouse mode to picking. This is the default.

Set viewport mouse mode to sub item picking. This lets you select objects that are in groups, parts and footprints.

Select all objects on the current sheet.

Invert the selection on the current sheet. Selected objects are deselected and unselected objects are selected.

Unselect all objects on the current sheet.

Lock all selected objects. This prevents them from being moved, modified or deleted.

Unlock all selected objects.

Rotate

Rotate selected objects 90 degrees clockwise about the command center of all objects.

Rotate selected objects 180 degrees about the command center of all objects.

Rotate selected objects 90 degrees anti-clockwise about the command center of all objects.

Mirror

Mirror the selected objects vertically about the common horizontal center.

Mirror the selected objects horizontally about the common vertical center.

Group

Group all the selected objects.

Ungroup all selected groups.

Layer

This will display the Layer Editor modeless dialog box. so you can add/rename/delete layers and set their colors.

Array

Create a rectangular array of the selected objects. This will display the Rectangular Array modeless dialog box.

Create a circular array of the selected objects. This will display the Circular Array modeless dialog box.