These symptoms look like Peach Leaf Curl, a very common fungal infection on peaches and their stone fruit relatives. Once symptoms manifest, it is too late to treat as there are no curative options. Fungicide prevention is used around November or very early spring (perhaps February or March) to kill overwintering spores before they can infect the buds. As noted in the linked page above, to compensate for some leaf loss due to the infection, thin the fruits so that the tree has a lighter load of peaches this year, or else the resource drain on the tree may make it more prone to additional problems later this winter. Fungicide information is provided in the Home Fruit Disease and Insects management guide, which you can search for "peach leaf curl." More information about other ailments common to peach, plus plant care tips, can be found in our Growing Stone Fruits in a Home Garden page.

Miri