1.     Access the bookmarks sidebar by swiping from the left edge of the screen.
2.     Tap “History”.
3.     Tap and hold a history entry, and choose “Remove from history” from the pop-up menu. If you want to delete all browsing history. You can just choose "Clear history" to clear all browsing history in the exit window (pop-up).

Or 

1.    In "History", tap the gear icon in the top right corner. Click Manage on the bottom of the page.
2.    Click on the box of the history that you want to delete.
3.    Tap the trash can icon to the right of the history entry you want to delete. If you want to delete all browsing history. Tap the check icon in the top left corner when you are done deleting history entries.