Your daughter would need to join WikiTree. Then she can add her own test. If she is not an adult, I recommend you wait.
Your daughter's father's DNA will be more useful than your daughter's for the ancestors in his line. If you have both his and your own results, your daughter's test will add no useful information. If that is not possible, then your daughter's DNA will be useful for her father's line, and if she joins WT as I've mentioned, she can post her DNA test information.
Whether or not your daughter's father was tested, it would still be quite useful to test his siblings, if he has any, or any of his older relatives still living.
Edited (twice) for clarity and additional information.
