How one can know that I am using JIRA Server or JIRA Cloud
Look at the link if it contains .atlassian.net then it is Cloud.
If it's old enough you may even have *.jira.com at the end of your URL, but Alexey is correct.
Its appearing as jira.<organizationname>.com
That means you're hosting it yourself, and it's Server.
Shannon
You can also check this way. If you login to Jira and choose the dashboard menu, then you will see the version of your Jira in the footer of the page. It means that you are on Server.
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