Utilitarianism is a normative ethical theory since it is theory about how we ought to act morally speaking. The simplest version says roughly: the morally optimal action is the action which maximizes future wellbeing.
There are various meta-ethical theories on the basis of which one might advance utilitarianism. Historically authors like Bentham and Mill focused on the natural grounding of value in seeking pleasure and avoiding pain. Sentimentalism/non-cognitivism has been a popular way to cash out this sort of meta-ethical justification of hedonic utilitarianism. However, there remains the added step of turning evaluative judgements (i.e. pleasure is good) into normative judgements (we should do what maximizes pleasure). In this regard, the utilitarian will often try to argue that overall value maximization is morally self-evident. This argument requires a more rationalistic/principlist (as opposed to non-cognitivist) meta-ethical grounding (see for example R. M. Hare). Thus, there is a tension within classic arguments for utilitarianism about which meta-ethical framework best supports the view.
Today, a moral philosopher who argues for a form a utilitarianism may well be neutral about underlying meta-ethics. Instead they are likely to sidestep meta-ethical issues entirely by adopting the shared methodological practices of contemporary normative theorists.