Most gardeners regard stinging nettles - Urtica dioica - as a weed, to be dug up and destroyed.
I have chosen to leave a couple of areas in my garden uncultivated, allowing native plants to grow to help wildlife. One of these is full of ivy, brambles and nettles:
I quite like the nettles; I find them fairly attractive, especially when in flower, and useful too. Here are some of the things you can use them for; unless you enjoy being stung always use gloves when picking and preparing nettles.
Feeding other plants
Nettles are rich in nitrogen, magnesium, iron and calcium making them a nutritious treat for lots of other plants. If you currently buy a compost activator / accelerator, using nettles has the same effect without the cost.
You can add nettles directly to your compost, although they're best chopped up first. Don't add their roots because these may survive the composting process and cause them to grow wherever you use the compost.
Alternatively you can turn them into a liquid fertilizer but be warned: this smells, so keep it away from the house! You can find a recipe here: https://www.amateurgardening.com/top-tips/make-your-own-nettle-feed-6537
Feeding yourself
Nettles are good for humans too, and actually pretty tasty. They're rich in rich in vitamins A, C and D as well as several beneficial minerals and even contain a fair amount of protein.
Young leaves are the best for cooking - older leaves may be bitter and can irritate the kidneys - so pick those at the top of the plant before it has flowered. Pick them using gloves and wash them carefully because they often have eggs clinging to their undersides. Strip the leaves from the stems and cook them in boiling water; this neutralises their sting and results in a green, leafy vegetable which tastes a bit like spinach. Then simply squeeze out the excess water and eat.
Nettles can be used in lots of dishes, here are a few recipes you might like to try:
Nettle and potato curry: https://www.naturalcookeryschool.com/nettle-potato-curry/
Stinging nettle pesto: https://www.smallfootprintfamily.com/how-to-use-stinging-nettles
Comercially, nettles are used in the manufacture of Cornish Yarg cheese (https://www.lynherdairies.co.uk/cornish-yarg/).
Drinks
It's really simple to make a nettle tea, just pour boiling water over clean fresh or dried leaves (remove the leaves before drinking).
You can also add fresh nettle leaves to give a juice or smoothie a nutritional boost (blending the leaves will eliminate the sting). Or if you fancy something a little stronger, Great British Chefs has an interesting recipe for nettle beer: https://www.greatbritishchefs.com/recipes/nettle-beer-recipe
Helping beneficial insects
A number of butterflies and moths including the Red Admiral, Peacock and Small Tortoiseshell lay their eggs on the underside of nettle leaves, and when the larvae hatch out they feed on the leaves. Ladybirds also favour them, and their larvae eat garden pests such as aphids, whitefly and red spider mite.
Aphids also love stinging nettles. It may seem counter-intuitive to want these anywhere near your garden, but they do act as a food source for some more beneficial birds and insects and a nettle patch may dissuade them from invading your more ornamental plants.
Clothing and fabrics
Nettles make a pleasant pale green dye for yarns and fabrics. If you're interested, you can find out how to use them for dyeing here: https://katiegrovestudios.com/2013/05/07/celebrate-stinging-nettles-a-recipe-for-nettle-dye/
Nettles have been used for making fabric for over 2,000 years. Making nettle fibre is probably something that most of us will not want to try for ourselves. If you're really keen, a book about how to create nettle yarn is available from Amazon. There are also a few specialist suppliers of nettle fabric clothese available on Etsy: https://www.etsy.com/uk/market/nettle_clothing.