how to make the canvas transparent

My canvas color is white canvas size in insert hight how to canvas hight area transpanrcny to white background

If you have an older version of photoshop, you can drag the padlock to the trashcan to convert a background layer into a normal layer.

Once that is done you have several options to choose from depending on the image if any is already on the canvas. You can create a selection and hit the delete key, you can use the eraser tool or you can create a mask from a selection.

It is totally up to you and what you are comfortable doing.

If you don't have an image, you could create a new document and choose a transparent background instead of a color. This can be found in the new dialog box.