My iCloud+ with 50 GB of Storage

The short answer is no, you can't transfer the subscription to your daughter but you have a couple of options.

I infer from your question that you do not have any other Apple hardware for use with iCloud. This may be incorrect, but presuming it is the case and if you have ceased using your iPhone you would have no further use for your iCloud+ subscription. In this case you should cancel your iCould+ subscription and set up a new subscription for your daughter. See Downgrade or cancel your iCloud+ plan.

In setting up her iCloud+ subscription, and depending on her age, you could use her payment method or enter your credit card in her Apple ID account. Be aware though that children under 13 cannot use a credit card as a payment method.

If in fact you do have other Apple hardware and intend to continue using iCloud you could continue with your iCloud+ plan and share your space with your daughter. This is achieved by starting a Family Sharing group, inviting her to your group and in accepting membership also accept to share the iCloud space of the organiser (ie. yourself). See Set up Family Sharing.