How to take photos with a mobile phone, blur the background and make the photos more layered?

This premise is that the mobile phone lens comes with a large aperture. For example, the latest Samsung galaxy s9 has a maximum aperture of f 1.2. In addition, outdoor lighting is better, such as sunny and mild afternoon, which can also be blurred well. However, the quality of mobile phone photos is still not as good as SLR. If it really doesn't work, use ps post-adjustment, draw a circle around the subject to blur, and then gradually adjust the blur.