There are the following methods for Rotate/Mirror when moving or placing an object.
When a component or pad is mirrored, the placement surface will be changed (Top surface => Bottom surface, Bottom surface => Top surface)

About the Operation and Method

The following will explain about rotating/mirroring objects.

The whole object is mirrored left-right.
For footprints and pads, components on the Top surface move to the Bottom surface, and components on the Bottom surface move to the Top surface.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Mirror]
(Press the shortcut "M" key)

The whole object is flipped vertically.
For footprints and pads, the Top/Bottom changes, and components on the Top surface move to the Bottom surface, and components on the Bottom surface move to the Top surface.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Flip Vertically]
(Press the shortcut "Shift + M" key)

While maintaining individual coordinates for footprints and pads, etc., components on the Top surface move to the Bottom surface, and components on the Bottom surface move to the Top surface.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Mirror Individually]

While maintaining individual coordinates for footprints and pads, etc., the Top/Bottom changes, and components on the Top surface move to the Bottom surface, and components on the Bottom surface move to the Top surface.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Vertical Flip Individually]

It rotates 90 degrees counter clockwise.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Rotate]
(Press the shortcut "R" key)

It rotates 90 degrees clockwise.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Reverse Clockwise]
(Press the shortcut "Shift + R" key)

It rotates 45 degrees counter clockwise.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Rotate 45 degrees]
(Press the shortcut "D4" key)

Specifies an arbitrary angle for rotation. When it is a positive number, it rotates counterclockwise, and when it is a negative number, it rotates clockwise.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Rotate Arbitrary Angle]

It rotates while maintaining individual coordinates for footprints and pads, etc., by inputting an arbitrary angle.
When it is a positive number, it rotates counterclockwise, and when it is a negative number, it rotates clockwise.
When moving an object or when it is selected, Right click => Select [Move/Rotate/Mirror] => [Individually Rotate Arbitrary Angle]

For more details about rotating and mirroring components, refer to "Rotating and Mirroring (Changing Placement Surface)" in "Placing Components" .

About Rotate and Individual Rotate

The following will explain the difference between Rotate and Individual Rotate.