Touch the left side of the LCD area to copy the displayed value (the X register) to the clipboard. A feedback alert is shown on screen.
The value is copied in a "spreadsheet-friendly" format: no thousand separators and point as decimal separator.
Touch the right side of the LCD area to open a quick guide for some operations of the calculator.
The vertical or portrait layout can be more practical if you like to use your phone in portrait orientation. If you don't like, you can go to Settings and lock orientation to Landscape.