What is the best certificate issuing service?

Question

Digital certificates

We are developing an application that customers will later connect to their sites.
Clients will rewrite DNS on domains, how can we solve the issue with SSL?
Through which service can I inexpensively configure the issuance of ssl certificates for domains?

Answer 1

Free, clear and fast.
https://letsencrypt.org/en/getting-started/

Answer 2

Do you want to just act as an issuing service or as a subCA? Of course, in both cases, you will need to negotiate with the real CA - if you plan to release for money. But the first case is simpler - you just collected the data from the user and transferred it to the CA, all the responsibility for issuing it, in the second case, the CA delegates the right to issue N certificates on its own behalf (he will obviously see what you issue there) and this the service is paid.