First, open our software and create a new file. The size of the file is set according to your needs. Then, set the foreground color to "light blue" and the background color to "dark blue".

Then we press "ctrl+shift+N" on the keyboard to create a new layer, and then select "Gradient Tool" on the left side of the software, select linear gradient, and select the first mode, as shown in the figure:

We use the gradient tool to pull the newly created layer from bottom to top, and get an effect of shallow bottom and deep blue top. Then we set the foreground and background to the default values, that is, the foreground is black and the background is white.

Then we choose "Filter-Render-Cloud" to get the effect of cloud.

Then we choose "filter-rendering-layered cloud" to get a deeper cloud effect, which may not be ideal. We can press "crtl+F" to continue adding layered clouds until we get the most perfect effect.

Now let's make the distinction between black and white more obvious. Select Image-Adjustment-Color Scale and set it in the pop-up box, as shown:

Enter the Layers panel, click on the layer 1, press "ctrl+J" on the keyboard to copy a new layer, and then select "Filter-Stylization-Protrusion".

In the "Protrusion" editing panel, set the parameters, as shown, and then get our effect.

Now set the blending mode of the upper two layers to "color filter" to blend in with the background. Then continue to click on the layer 1 and press "ctrl+J" to copy a new layer.

On the new layer, select Filter-Blur-Gaussian Blur and set the blur value, as shown:

Then we adjust the opacity of the three layers and slowly adjust it to get our cloud effect. I hope it will help everyone.