Bokeh

Bokeh, also known as “Boke” is one of the most popular subjects in photography. The reason why it is so popular, is because Bokeh makes photographs visually appealing, forcing us to focus our attention on a particular area of the image. The word comes from Japanese language, which literally translates as “blur”.https://photographylife.com/what-is-bokeh
To achieve the blurred background effect , I find setting the camera between F5.6 -F8 gives best results . Trial and error of these settings will give you the effect you want . Picking the right background is important  , foliage , grass , fairy lights are all good . Check the area infront and behind where you are taking the image . Remember to focus on your subject , single focus point is best , so the camera understands what you are wanting to capture , without it trying to get everything in focus Set up Nikon D7000, Tamron 70-300 mm , F8 , 1/320 , 300 mm