3rd party Certificate

What's it use for ? Personal web site or business web site or business web site with transaction ?

There are 2 major type of certificate, DV & OV. It's about how trust of the certificate requester.

For DV, the requester need to have a DNS domain for verify. (Less trusted of this certificate)

For OV, usually a organization which need vetted by the authority. (More trusted of this certificate)

Here some of the certificate you can buy, depends on your business needs.