You can install a certificate from any issuer on your hosting. The process has three parts.
1. Generate the request
In cPanel open SSL/TLS, then Generate, view, or delete SSL certificate signing requests. Fill in the domain and your details and cPanel produces two things: a private key, which stays here, and a CSR. Send the CSR to whoever you are buying from.
2. Complete validation
The issuer will ask you to prove you control the domain, usually by email to an address at that domain, by a DNS record, or by placing a file on the site. Follow their instructions; we can add a DNS record for you if you use our nameservers.
3. Install it
When the certificate comes back, open SSL/TLS, then Manage SSL sites. Choose the domain, paste in the certificate, and cPanel will match it to the private key it kept. Paste the CA bundle the issuer supplied into the third box – leaving that out is the single most common installation mistake and causes the certificate to fail on some devices while working fine on others.
Afterwards
Your purchased certificate takes precedence over the automatic one. When it expires you must renew and reinstall it yourself; nothing renews it for you. If you later let it lapse, remove it and AutoSSL will take the domain back over.
If you would rather not do this yourself, open a ticket with the certificate files and we will install it.