You need to be a qualified nurse. You then apply to a health authority for sponsorship and a place at Uni at the same time to do a BA Hons course in community health. Two years later you qualify and hope that the sponsoring ha will offer you a job.
It helps to have a steady stomach, a sense of humour, your own children, a supportive partner/family and the ability to hold your own when necessary. There are also huge amounts of paperwork and regulations that you need to be able to put up with and get on with.
I often felt like a glorified social worker - impotent (you couldn't just wave a magic wand and make everything - or sometimes anything - better) but I think it depends hugely on where you work and the particular ha. I taught a single dad how to cook beans on toast/use the washing machine/what a brownies uniform consisted of. I had a mother with pnd kill herself. I had cot deaths. I had children who flourished in spite of everything. I had a beaten mother turn round and press charges and watched her blossom as she made it by herself. I signed children into care. I was thumped, threatened, bitten by a dog, kissed and hugged, had huge buffet feasts cooked for me, drank tea that made me heave, there are families I will always remember and others I try hard to forget.
It is not for the fainthearted and is often a thankless job. There are good and bad hvs. Most of my colleagues were great. One went off and became a female priest! Another died recently aged 39 of cancer and had many of the families on her caseload contact her husband to say how much they missed her.
Having said all that, don't miss the job at all and in fact moved out and into a specialised field quite early into my career.
But you really need to ask a current hv all this...