Select Trim Leading Whitespace in the Extra menu to remove whitespace from the start of each line. If you selected part of the file, only lines that area selected will be trimmed. If not, all lines in the file will be trimmed.
If you've made a rectangular selection, EditPad Pro will only delete whitespace inside the rectangular block. Whitespace in the leftmost selected column and adjacent columns to the right will be deleted. This whitespace needn't be at the start of the line
Extra|Trim Trailing Whitespace
Extra|Delete Blank Lines
Extra|Consolidate Blank Lines