The difference between acute angle anchor point and rounded angle anchor point of PS pen tool is hard anchor point without tangent, anchor point with parallel left and right tangents and anchor point with non-parallel left and right tangents.

The tracing tool is a supplement to the pen tool. It is usually used for matting. First use the pen tool to select the important turning points one by one, and finally select the starting point, so that the whole is selected, and then use the tracing tool.

Click the anchor point with the deformation point tool, and you can switch between the anchor point without tangent and the left and right tangent at will.