Yes, you can send it to her bank account even if she isn’t using Monzo.
Just select ‘Payments’ along the bottom then ‘Bank Transfer’.
If you are sending it to a UK account then fill out her info and then the amount you want to send her. They transfer is normally completed in a minute.
If you are sending outside the UK then fill out the payee name and the currency you want to send. Sending to non UK accounts uses TransferWise and so there is a fee for doing so.
If you sign up to the labs feature you can send her the money using text or email, even if they don’t have a Monzo account. I’m not exactly sure how this works as I’ve never used it before.
Here’s the blog post about it, seems easy enough to do and no fees: Monzo Labs: Pay anyone by text or email