Here's how it works:

* Proteins are synthesized by ribosomes.

* Proteins are transported to the Golgi apparatus.

* In the Golgi, proteins are modified, sorted, and packaged. This includes adding tags, like:

* Glycosylation: Adding sugar molecules.

* Phosphorylation: Adding phosphate groups.

* Lipid modifications: Adding lipids.

* These tags act as "address labels" directing the proteins to their final destination, whether it's:

* Secretion outside the cell

* Delivery to other organelles

* Insertion into the cell membrane

So, while the Golgi apparatus doesn't directly "tag" proteins in the sense of attaching labels, it modifies them in ways that act as tags for their eventual sorting and distribution.