When I started photography the first type of picture that drew my attention was the one where the background is blurred and the main subject comes out in the picture like the sample below.
In this picture the bird and some part of the tree are clear and the other are blurred. After studying and reading I realized that primarily is a lens feature and lenses with an aperture size of 1, 1.4, 1.8 and 2.8 F are critical in achieving the results. These are called the fast lenses and can work in low light conditions. While the pictures have to be taken in manual settings primarily to get the bokeh effect.
Simple prime lenses of low cost like a 1.8 F 50 MM can create these pictures with a DSLR. The sad part of the new smart phone which keeps on boasting of higher Mega pixel will never be able to get you the real effects of photography. Anyway good for selfies and immediate photos the smart phone have their advantages. Some may debate that there are apps to create the Blur but the finer effect can never be created through apps.
So if you want to get beautiful effects and lifetime memories please start using a DSLR. You may reach out to me for better understanding of this setting.