If you need to Purchase a McAfee SaaS endpoint software and create a new McAfee Account, you need to open the webpage
www.mcafeeasap.com and on the top you shall see a tab that says "Services", select the service that suits you the best and click on it.
Now, you will be given an option to "Buy" or "Try". If you click on buy you need to create an account with your Credit card details and purchase the software, Alternatively you can select "Try" and you will just be asked to use an email address and a password to create a trial account.
Now, you can create a new account and you can download the software from that account.
Please reply for more clarifications.