PALETTES in Illustrator tell you what is going on with specific parts of artwork you have created and help you to make changes to that artwork.

When you open Illustrator, you will see different sets of floating PALETTES in default groups.

To bring a PALETTE to the front of it’s group, click on the tab that shows the PALETTE'S name and the PALETTE you want will appear on top.

Go to WINDOW in your menu bar at the top of your workspace. Here you will find a list of all of the PALETTES available to you.

A check mark next to a PALETTE name means that a particular PALETTE is currently displayed on screen in the front of it’s group. To remove a PALETTE that is floating on your screen, scroll down to that PALETTE name and release your mouse and the PALETTE will disappear from your workspace.
You can rearrange the PALETTE groups if you wish to make your workflow easier. All you need to do is click on the tab of the PALETTE you wish to move and drag it to another group.

Many of Illustrator’s PALETTES can be viewed by name, or from a minimal, compact, or expanded view. If the PALETTE tab has a double triangle to the left of the PALETTE name, click on it to see the different views of the PALETTE.