Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
What do you mean, "OV or SSL"? OV is a type of SSL certificate, and as @rg305 has already told you, it's one that Let's Encrypt doesn't provide--it only provides DV certs. If you need an OV cert, you'll need to get it from a different CA.
If you just want to get an ordinary SSL certificate, start by reading the documentation:
What kind of hosting? If you're using their web hosting, or their managed servers, getting and installing the certificate would be their problem (and it's something they say they include with both of those), and you'd need to ask them. If you're using one of their "self-managed servers", go back to the documentation link I already gave you and read it.