Why did I get a text from my daughter's phone that she didn't send?

Number spoofing is one possibility. A text can display a familiar number even when it wasn't sent from that person's phone, so the missing sent message does not by itself mean her phone was hacked.

Don't follow links or reply to the message. If it asks for anything, check with your daughter another way. If more messages appear, save the details and ask your carrier to investigate.

First check whether it was actually a text or a voicemail transcription shown in the conversation. Some carriers provide voicemail transcripts, and garbled transcription can look pretty strange.

That doesn't explain everything if it really was sent as a text from her number, though. Check the message details and voicemail before assuming that's the answer.

There's not enough here to tell if the phone is compromised. Check for other unusual activity, keep the phone updated, and contact the carrier if the messages keep coming. A single unexpected text isn't much to diagnose from.