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.
As an English name it has been in use since the Middle Ages, originally in the form Clare, though the Latinate spelling Clara overtook it in the 19th century and became very popular. It declined through most of the 20th century (being eclipsed by the French form Claire in English-speaking countries), though it has since recovered somewhat.
This name was fairly common in France, England and the United States in the early 20th century. It became quite popular in France and England at the end of the 20th century, just when it was at a low point in the United States. It quickly climbed the American charts and entered the top ten in 2014.
This name experienced a rise in popularity at the end of the 20th century. It was the most popular name for girls in England and Wales from 2011 to 2015.