They’ll likely direct you to the Admissions website: https://barnard.edu/admissions/testing
https://barnard.edu/news/barnard-implements-test-optional-admission-policy-one-year
Does your daughter have other tests, such as AP exams or SAT Subject Tests? If so, that’s a good way to show academic strength, especially if in the subjects your daughter is interested in, if you’re unable to submit a SAT/ACT score.