Just enter her under My Info and answer the questions. If she was on your last year return she should transfer over. You might have to answer a couple questions like what is her income and if she is a full time student. Turbo Tax will automatically give you the Other Dependent credit if she qualifies. See my screenshot on this one. It shows where it is checked on the 1040.
https://ttlc.intuit.com/community/file-with-turbotax/discussion/senior-in-high-school/00/2785443
