Have a bit of a search, questions about NHS interviews do come up quite regularly. My advice would be read back over the advert and the person spec for the job (should be saved on your NHS jobs account), this should give you plenty of clues about what they are likely to ask you about. Usually there will be some introductory questions about you, your career history, why you want the role, your strengths and weaknesses/developmental points. There may be some technical questions about the software or systems they use in the role and your experience of using these or similar systems, about your experience/knowledge of relevant things like governance, meeting administration, budget management, HR or line management if required, safeguarding, equality and diversity. And there will probably be some more 'competency'/aptitude type questions on things like team-working, organisation and prioritization skills, customer service, problem solving, identifying and making improvements. When preparing for an interview, as well as thinking of well structured answers to questions like why I want the job and why I'd be a good fit for the role, I read through the person spec and make a list of what seem to be their top 5 - 10 qualities/competencies/skills they want and come up with a list of examples from my experience that demonstrate those - it doesn't have to be exactly one for one, e.g. an example about performance managing a difficult team member could be an answer for questions about line management, conflict resolution, leadership, problem solving etc. So if I haven't guessed exactly correctly what they'll ask I still have all my examples ready to go - I write each one out in a STAR format (situation, task, action, result) as this helps structure the answer and minimise nervous waffling or losing my train of thought.
Finally make sure to prepare some intelligent, interesting questions for the 'Any questions for us?' section, I always think that's a bit of a trick as it's not really the appropriate time to be asking the practical questions you want answers to like 'when will I hear back?', 'is there scope for salary/hours/flexible working negotiation' and so on, and more an additional chance to sell yourself as an enthusiastic and knowledgeable candidate - I tend to ask one question about the organisation such as asking about a new initiative or change programme I've seen on their website and then one more about the job itself or the team - e.g. whether it's a new role or existing and why is it vacant, is the team well-established or newly formed, that sort of thing.
Good luck!