I have written same html code to display 2 horizontal line but I'm getting 2 horizontal line with different thikness

I'm using VS Code in my Windows 10 OS. I'm a beginner in Web Development. I wanted to display 2 horizontal line. I used same code i.e., <hr size:"2" color:"black"> for getting 2 line disply, but I'm getting 2 lines having different thikness. I also used CSS in hr tag as style="size: 2px; color: black", still I'm getting lines with different thikness. Plese tell me why is that happening and give me the solution.