After all these steps, it is time to save and share your graph. You add ggsave('NAME OF THE FILE) right after you plot the graph and it will be stored on the hard drive.
The graph is saved in the working directory. To check the working directory, you can run this code:
Let's plot your fantastic graph, saves it and check the location
x = "Drat definition, in log",
y = "Mile per hours, in log",
color = "Gear",
title = "Relation between Mile per hours and drat",
subtitle = "Relationship break down by gear class",
caption = "Authors own computation"