I have been using MSOffice for 15+ years and have created thousands of documents in Bookman Old Style. It is not on the list in LibreOffice which I have recently started using so would like to find out the above question. I have not been able to find an answer in Help despite an hours worth of searching!
You don’t import fonts into LO. LO uses whatever font is available on your machine. If you need a specific font, install into your OS.
Note however that “old” fonts may not be compatible with LO or OS font renderer. LO dropped support fo “Type 1” fonts a few years ago. Most “OpenType” or “TrueType” fonts should be OK.
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