Two musical producers are trying to scrape enough money together to finance their show. When one of their backers doesn't show. They convince female impresonator Tim Moore to impresonate the second female backer. Although it's release date is is 1947 it was passed by the National Board of Review in 1946.
You can stream Boy! What a Girl! (1946) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.