padding

border

structure

margin

inside an element's border

outside an element's border

inside an element's border and includes the border 

inside as well as outside the element's border, depending on your needs

p {
  background-color: salmon;
  color: white;
  width: 100px;
  border: 1px solid black;
}

p {
  background-color: salmon;
  color: white;
  width: 100px;
  text-align: center;
  padding: 10px;
  border-radius: 5px;
}

p {
  background-color: salmon;
  color: white;
  width: 100px;
  margin: 80px;
}

p {
  background-color: salmon;
  color: white;
  width: 100px;
  padding: 300px auto;
  margin: 100px;
  border: 10px double black;
}