How was born in Bideford, Devon to a family of silversmiths. She was the youngest of her family, and both of her parents died before she was an adult. She moved with her family to Bournesmouth and attended the Herkomer School at Bushey, Hertfordshire. She then moved to Paris to study at the Academie Delecluse around 1893, and began exhibiting in 1902 at the Societe Nationale des Beaux-Arts, where she exhibited around 147 works throughout her career. While in Paris, she was introduced to the work of Rodin, Polin, Besnard and Lucien Simon, whose works may have influenced her art. She eventually set up a workshop in Étaples. How painted various subjects, including nudes, portraits of children, and fruit and flower studies, and worked using a variety of media, including pastels, crayons, oils, and watercolors. How was "considered on par with Berthe Morisot and Mary Cassatt" in France and America, but was "somewhat neglected in her country of origin." How's works were included in various exhibitions in France, Britain, and abroad. These exhibitions included the Royal Scottish Academy, the Royal Glasgow Institute, the Royal Academy, the Liverpool Autumn Exhibitions, Beaux Arts Gallery, Galeries Georges Petit, Galeries des Artistes Francais, Salon des Tuileries, and the Carnegie Exhibition. After her death in 1932, a memorial exhibition was held at the Beaux ArtsGallery in 1933 and at the New Burlington Galleries in 1935. How won an Honourable Mention at the Carnegie Exhibition in 1914 and was elected as an Associate of the Societe Nationale des Beaux-Arts in 1904. In 1905 two of her paintings, In a Dutch Cottage and Le Repas were included in Women Painters of the World, an overview of women painters with the remark "Miss Beatrice How...gives us, most delightfully, the very sentiment of the country people she paints." How is most recognized for her art depicting mothers and children. According to the Kourd Gallery, "Her fragile technique and the masterly handling of the lowest tones give so much vitality to her paintings that they seem almost transparent." How never married or had children. She died in 1932 after falling at her niece's home in Hertford.
