Yearly licences are valid for a year. During that time you are entitled to receive free updates and support. After 12 months, yearly licences will automatically renew. You can cancel at any time.
Lifetime licences are a single, one-off payment. Lifetime licences do not expire and you are entitled to receive free updates and support for the lifetime of the product.
You can purchase a Yearly licence then upgrade to Lifetime if you wish. Upgrade within the first year to just pay the difference.