Evergreen pleached trees https://justpleachy.co.uk/collections/evergreen-pleached-trees Set them about 0.5m from the fence and you should be good. More on reddit.com

Edit: apologies - after I'd written this, I realised that I may have misread your post. These recommendations are for hedges which will provide privacy from people on the ground - if you're after things to make a tall tree line for privacy from upstairs windows, this is probably less useful. It depends what your priorities are. A mixed hedge of native plants is by far the most beautiful and best for wildlife. This sort of hedge will provide flowers and fruits for birds, animals and humans (blackberries). While many native hedging plants lose their leaves in winter, some don't, and if you plant the hedge at the right density and maintain it you won't lose any privacy. You should look up hedging plants where you are: where I am in the South East, the recommendation is this: A Good Planting Mix: 70% from a choice of hawthorn, blackthorn, buckthorn, privet, beech, hazel and dog rose. 25% from a choice of guelder rose, field maple, spindle, crab apple, holly and yew. 5% from a choice of climbers, such as honeysuckle, blackberry, ivy and native clematis. If this is more effort than you are willing to put in, the best and traditional alternative is yew. It is evergreen, basically immortal (I would recommend this unbelievable fascinating radio programme on yew - https://www.bbc.co.uk/programmes/b082ymp5 ), and good for wildlife. The trick is to prune the plants at the side all the way down as well as at the top to get it thicker more quickly. It is slower growing than these other plants: it will take five years for young plants to get to 6ft - obviously a shorter time if you buy bigger plants. But as the excellent gardener James Wong says, 'I never understand people who say they don't have time for yew: what are you going to do, move?' He's right in the sense that years later many people wish they had planted yew, as there's really nothing else like it. If these options don't sound like they're for you, you can use some of the fast-growing, non-native hedging plants. Fortunately the utterly awful leylandii seems to be disappearing and is being replaced by things like cherry laurel. These hedging plants tend to be pretty worthless for wildlife, and are often very ugly in my opinion, but will grow fast and are evergreen if that is your priority. More on reddit.com