Full tutorial on how to use whitelist on your server in Minecraft on any version
All commands must be typed in the server console.
whitelist add player_name - adds a new player to the whitelist
whitelist remove player_name - Removes a player from the whitelist.
whitelist list - Displays all players on the whitelist.
whitelist on - Enables the whitelist on the server.
whitelist off - disables the whitelist on the server
whitelist reload - reloads the list of players in the whitelist if it has not been changed manually via the server console.