I don't know how to use like eraser to remove the highlight or the signature.
On the other hand, I want to draw something in pdf, but adobe only can highlight, edit the original format,signature...etc, can't let me draw(I want to try use signature pen to draw, but fail and stay the spot like attach picture.), how can I draw?
It's hard to tell from your screenshot but have you gone into Edit mode and then with the arrow cursor tried to click on the items you wish to delete, make them active, and then click on the Delete/Backspace key to remove them?
As far as drawing goes, there is limited drawing capability in the Comment Tool as shown below:
Once you click that you can change the color to the right as well as change the line thickness as shown below.
Be aware that you cannot vary line thickness as you could do with something like a Wacom tablet. There is only one thickness at a time. Also, since this is the Comment Tool you are using, as you use this there are options to add comments in the Panel on the right. If you have nothing to comment about whatever you are drawing, just ignore this and keep on drawing.