This is not the usual spelling in any of the Scandinavian languages (in Sweden and Denmark it is Freja and in Norway it is Frøja) but it is the common spelling of the goddess's name in English. In the 2000s it became popular in Britain.
The Cornish form of this name, Jennifer, has become popular in the English-speaking world.
As a Russian name, this is an alternate transcription of Людмила (usually rendered Lyudmila).