Files, the database and WordPress are not a separate product. If you bought Linux hosting, they are in cPanel. If you bought Windows hosting, they are in Plesk. While the account is being prepared the button stays hidden. When it is open, you enter from the same card.
WordPress is not its own package
WordPress is an install inside that panel. When the install finishes, the management address is /wp-admin on the site. The password is the one you typed during install. An empty site opens from the same panel.
Which shelf
Linux hosting comes with cPanel. Windows hosting comes with Plesk. The multi-site Windows package is on the multi-site shelf. A dedicated server does not carry these buttons. When it is ready, the address and the user appear on its own card.