Tap “History“

Tap  menu icon on the right side of videos.

Tap “Remove from Watch history“

This is how you remove Watch history individually.

Tap  menu icon on the top right.

Tap “Settings“

Tap “Clear watch history”

Tap “CLEAR HISTORY”
This is how you clear all history at once.

Tap “Clear search history”

Tap “CLEAR HISTORY”

Well done!
History is empty now!