What do you mean by "serial number"?
A serial number is usually a unique identifier for something, which, in Jira, is done with the issue key. So you already have what is effectively a "serial number" on screen.
That makes me think you mean something else by "serial number" - could you explain what you would like to see in the column you want to add?
your question could be understood in a way each issue is using a custom field where a value for "Serial Number" is entered.
Further one could assume you now want to display the serialnumber alongside with each issue in Issue Navigator.
If this is correct you can click on "Columns", select "Serial Number" (the Custom Field you created for holding a serial number).
The result should look like this:
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