Source: https://howchoo.com/pi/raspberry-pi-display-rotation
Open file
sudo nano /boot/config.txt
Rotate the display
display_rotate=0 # Normal (landscape)
display_rotate=1 # 90 degrees (portrait, upside down)
display_rotate=2 # 180 degrees (landscape)
display_rotate=3 # 270 degrees (portrait, upside down)
display_rotate=0x10000 # horizontal flip
display_rotate=0x20000 # vertical flip
Rotate touch input
lcd_rotate=0 # default (normal landscape)
lcd_rotate=1 # 90 degrees (portrait, upside down)
lcd_rotate=2 # 180 degrees (landscape)
lcd_rotate=3 # 270 degrees (portrait, upside down)
Reboot the device