sign in

/S AY1 N IH0 N/
verb
  1. 1

    To sign one's name on a list when entering a place, to indicate one's arrival.

    โ€œIn order to get into the office after hours, you'll have to sign in at the security desk.โ€

  2. 2

    To take some action to access a secured program or web page on a computer; to log in.

Source: https://en.wiktionary.org/wiki/sign%20in