Place the mask
Choose Blur. Fit its box over the target by dragging and resizing the handles. Rectangle, Oval and Rounded control the actual mask shape. Light, Normal and Strong start with different strength values.
Control the result
Strength continuously changes Gaussian blur. Pixelated uses real blocks; Block size changes their size. At zero the effect is off but the editing outline remains. Always review playback and the exported result before sharing sensitive footage.
Track movement
Use Track area for a boxed object, Find & track face for a clear frontal face, or Manual to record positions yourself. Short ranges inside one shot are easier to track than cuts or long occlusions.
Example: cover a moving detail
Set the blur interval to one continuous shot. Pause on a clear frame, fit the mask over the detail, choose its shape and increase strength until the detail is hidden in playback.
Track the area if it moves. Add a little coverage around the edges so small tracking changes do not uncover it. Review the beginning, middle and end in the exported file.
Blur or pixelation
Gaussian blur softens detail continuously. Pixelation replaces it with blocks; increasing block size makes the blocks larger. Rectangle, Oval and Rounded describe the mask boundary, not the blur algorithm.
A visible editing outline does not prove the effect is strong enough: a zero-strength effect can still have an outline.