When purchasing a Server/VPS, you will be requested to enter a Host Name, and Root Password. You may enter any single word as the hostname - this is just a name for your server, so you can enter something like ‘server1’, or ‘mysneakerserver’, and it would be accepted as your server's hostname accordingly. Please do not use any special characters like % or ! or * ^ $ , as these are cannot be accepted for the hostname. Also, please do not enter a blank space (in between the words), as that is not accepted as well.
And as for the root password, this is simply your server's login password. Please enter a password that has at least 12 characters, contain at least 1 upper case, 1 number, and if you are able to include 1 or more special characters into the password (eg: # @ ! $ % & * ), that would ensure a safer and more secure password for your server.