Multiple domains, 1 server. What kind of SSL certificate is needed?

Question

Digital certificates

Colleagues, I welcome
Help to solve a problem on SSL please.
I have a server with one IP.
It has n-tsat domains. And such here feature: all domains are actually processed by the same php-code.
That is, we open domain.ru, domain_1.ru, domain_xxx.ru - the server sends everything to the same vhost by default.
On http everything works fine.
I need to make SSL certificates for all these domains and access via https.
What SSL certificates to buy? Is there a separate certificate for each domain or is there an option to take it for all domains running on this server?
Will certificates for each domain be put on one server with one IP?
The most important thing is that when you open any of the domains served by this server in a browser, you can process them with the same code. Essentially like aliases or mirrors.

Answer 1

There are several options.
Either a Wildcard certificate, if subdomain protection is needed, like:
payments.yourdomain.com
login.yourdomain.com
mail.yourdomain.com
Or a multi-domain certificate, if you need unified protection for different domains like:
www.website.com
any-domain.ru
secure. website1.co.uk
But often only a few domains are included in the price of such a certificate (for example 3) and there is a need to pay extra for each domain in addition to the tariff.
So you can consider the option of a simple certificate for each domain.
Depending on what will be more profitable in this situation.

Answer 2

Thank you.
Cut :)