Simply sign out of your ID and sign in with hers without erasing the device. As she does so she will be asked various times if she wants to keep the existing data. Say yes to the ones you want her to keep. You may also want to go through various Settings and make sure there aren't any still set to your ID, or for things you do not want her to have. If something is set to your ID and it uses iCloud you may suddenly find things changing on your device as she changes them on hers. In theory you would do a full erase before giving her the phone but since you do not want to do that...
Note that while apps will be kept, in order to update them or redownload content purchased with your ID, she will not be able to get them with her ID unless you turn on Family Sharing and share the purchases with her.
Articles you may find useful:
Set up Family Sharing - Apple Support
How to create a new Apple ID - Apple Support
Create an Apple ID for your child - Apple Support
How to download apps and content that your family members purchased - Apple Support
How to share purchases with your family - Apple Support