Question

Why is it important to know who created a source?

Answer 1

adding to what the other guy said the biased of the source helps. ex. a source of a british imperialist will be greatly different than a source from and indian or african person that has been colonized

Answer 2

When analysing a source, you need to be aware of when it was made. This will not only help you to determine whether it is a primary or secondary source, but it will also help you in your source evaluation.