The intention is that you first install this font on your server machine.
How can you install a font? Well, this is really simple on Windows. I tested my setup on Windows Server 2008 R2.
Just copy your ttf file(s) (downloaded from the www, or supplied by a third party) to the "C:\Windows\Fonts" directory and restart your server machine.
When this is done, you will see your barcode font(s) in Reports Builder.
And you can start using your barcode font type.
If you run afterwards your report, you will not see the desired output.
That's because you'll have to so some other additional modifications.
The default Fonts directory has to be added to the REPORTS_PATH variable.
If you work with reports environements, then go to the "Basic Configuration" section and add "C:\Windows\Fonts\" to the REPORTS_PATH variable:
In the "Forms/Reports Common Configuration", add the barcode font to the "PDF Subsetting":
This file must be copied to the "%ORACLE_HOME%\tools\common\" directory.
Then, run your report and see that the barcode shows up correctly in your report: