A pen is a type of materialistic thing which is used for writing and drawing purposes. It contains an ink by which we can write on a surface such as paper. Its ink contains different chemicals like Tannic Acid, Crystallized Ferrous Sulfate, Gum Arabic, etc. Earlier, people were using dip pens, reed pens, etc., but now people are using modern pens like ballpoint pens, ceramic tip pens, fountain pens, etc.