In Devanagari script, upper and lower cases do not exist. In turn, though, Devanagari precisely reflects pronunciation. Below, you will find an explanation of the lines of individual letters.
In Devanagari script, we right from left to right and from top to bottom. As a last step, the letters are attached to a horizontal line above them. Even when we write an entire word, this horizontal line is drawn over the complete word.