Reference line:

ctrl+R？ Adjust the upper ruler and the left ruler, and then drag a line down the ruler to the desired position. This is the reference line.

Solid line 1:

Click the mouse on the box selection tool to open the drop-down menu, as shown in figure 1, and select "single-line box selection tool (drawing horizontal lines)" or "single-line box selection tool (drawing vertical lines)". Click on the position you want on the canvas, and a check box will appear on the canvas. alt？ +? Backspace fills the foreground color, ctrl+d? Uncheck the box and a boundary will be drawn.

Solid line 2:

Select the line tool (as shown in Figure 2) and pull out the lines you want directly on the canvas. (Tip: Hold down shift and pull the wire to draw a straight line).