Subscription is a type of license which works for a limited amount of time. After the license expires it should be renewed to be able to work with software.
If you purchase subscription for a program and choose "Visa & MasterCard" payment method then the license will be automatically renewed and your card will be periodically rebilled.
For example, if you select "Subscription for 2 PC. Charged every month - 9.95 USD" then when the purchased license expires (a month after first purchase) your card will be automatically charged for another 9.95 USD.
Any other payment method do not use automatic license renewal. Instead you will get an Email message with an annotation, that your license will expire soon. In this case you should prolong your license manually.
You can cancel your subscription at any time using the "Unsubscribe" option.
Lifetime licenses are purchased once and work forever, without any limits.