Of course you can often find short bios by entering an artist’s name in a search engine and these can work fine if you examine them carefully. In general, the biographies posted by major museums, art galleries, and artists themselves, are of a higher quality than those provided by the many commercial sites such as Artcyclopedia, AskArt, Artnet, etc. Accuracy varies. Web bios for historic figures are frequently copied from public domain (pre-1923) sources.
Since there are so many biographical dictionaries to choose from, indexes have been designed to show you exactly which dictionary will contain a biography of your artist. There are 2 indexes that cover arts people.
Try them in this order:
Curators, Educators, Gallerists, Critics, etc.
The most recent volumes of these are not covered in indexes and must be checked separately: