Straight cash only. Gift cards are a scam. An interest-free loan to the company selling them, which they only have to pay back when the card is used, or never if it isn't used in time, and the recipient doesn't get a choice where to spend it nor put it towards anything they're saving up for.
My heart used to sink every time I got a gift card, requiring me to be organised enough to keep it safe and remember to take it with me into town. Worst present ever. Sorry.
*I'm sure there are exceptions, if you know the person well enough. But if you don't know what to buy them, you probably don't know them well enough. And you're still giving scammers an interest-free loan.
unless the drinking age is 21 where they live.... (in the us. yes. we're puritanical.)
I second the books. Go to a bookstore and find something that would make you both laugh.
Another option is if she's into any sort of crafts. Knitting, maybe? (but only if you KNOW. and then I highly recomend gift cards. or at the very least receipts.)
finally, does anybody say 'no' to their favorite candy?
depending on how good you guys know each other you could gift her an event that you both can go to together (concert, cinema(barbenheimer;), bowling etc)
If you know of her favorite movie or TV star, musical favorite, internet or YouTube ‘star’, or something similar look through Cameo and see if they are on the site. They have hundreds of popular (and obscure) choices to send a birthday message personalized to her, many of which would have the video sent to you in a matter of hours but she might treasure for a long time.
Either a tangle free hairbrush or a hairbrush with ions, almost every female has a tangle free brush but they are always old and needs replacing. Not a lot of them have ion hairbrushes that help remove static from hair.
No, that means you understand women, I have 3 sisters, every 5 years i gift them brushes for smaller ocasions like valentine, they usualy are happy and use the new one for a long time. Somehow they love boxes too, they put jewlery, small appliences in to them.
What about a gift card to a streaming service? I don't know that is available where she is located. You could gift a few months of something like Hulu or Max with some suggestions of movies or TV shows to watch.
You could also gift something like Spotify Premium and include suggestions for new artists that you think she'd like or even build a playlist to share with her.