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.
My domain is: avaya
I ran this command: n/a
It produced this output:
My web server is (include version):
The operating system my web server runs on is (include version):
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don't know):
I'm using a control panel to manage my site (no, or provide the name and version of the control panel):
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot):
That's really a support question for Avaya, since you are likely paying them a lot for that, however getting a cert and using it are two different things often done at the same time:
Use an ACME software tool to get the certificate you need to cover the fully qualified name of your service e.g. something.yourdomain.com. You can't get publicly trusted certs for internal names unless they are fully qualified with the domain. Which ACME client depends largely on what's already being used in your organization (if you are "enterprise" you likely already have hundreds of certs happening) and tho some extent which operating systems you are using.
Using a cert (deployment) is the act of applying a certificate to a service, usually as one or more component files, the service typically loads the certificate file and uses it for TLS conversations. Often (but not always) services need restarted after a new certificate is applied, some more capable services can dynamically load the latest cert without restarting.
Note that it's not clear from your question whether you are a seasoned IT professional, a non-IT person or if you've just finished high school, so we don't know at what technical level to pitch the answers.