The general process: first make the background, you can use the material directly; then set the desired text, and use a smoke or cloud brush to smear along the text to make cloud characters, or you can directly stroke the path ; You can add decoration later.
To create the cloud font in ps, first type with the text tool, adjust the typing size, and rasterize the text. Execute Filter--Brush Stroke--Spray Stroke, OK.
Steps to draw crystal clear clouds in PS: Open the PS software and create a new canvas of 500*400 pixels.