。
She may use this typewriter.
Literal
She [topic-は] this typewriter [object-を] use [even-if-てもよろしい].
~てもよろしい is the formal/polite permission form, using よろしい ('good, acceptable') in place of plain いい. Slightly more formal than the everyday ~てもいい, though still natural in any polite context — common in service settings, formal speeches, or when granting permission from a position of authority. タイプライター ('typewriter') is an English loanword that's now somewhat dated, since most writing has shifted to keyboards on computers — encountering it in modern Japanese signals an older or stylized context.