Which organelle is responsible for storing, modifying and sending out products of the endoplasmic reticulum, such as proteins?

The Golgi apparatus is the cell organelle responsible for packaging, processing, and shipping proteins from the endoplasmic reticulum (ER) throughout the cell.
Lysosomes are the digestive system of the cell. Lysosomes contain hydrolytic enzymes which allow them to hydrolyze (break down) proteins, fats, sugars, and nucleic acids taken into the cell as well as break down other worn out organelles within the cell. Lysosomes contain an acidic environment with a pH of around 4.5.
Ribosomes are responsible for protein synthesis. Ribosomes read RNA produced in the nucleus and translate the genetic instructions provided to produce proteins. Cells with a high rate of protein synthesis typically contain a high number of ribosomes.
The endoplasmic reticulum is an organelle that is attached to the nuclear membrane and has two continuous parts: the rough ER and smooth ER. The rough ER is the part of the endoplasmic reticulum that is covered in ribosomes, which gives it its rough appearance (see diagram below). The rough ER is responsible for membrane production and is the site of protein synthesis. The smooth ER is responsible for the detoxification and metabolism of multiple molecules. Its other functions include synthesis of carbohydrates, lipids, and steroid hormones; and the storage of calcium ions used for muscle contraction.