By default, the Finder displays a sidebar when it opens.
If you prefer to hide the sidebar, in the Finder menu bar, selectView>Hide Sidebar.
To reopen the sidebar after you close it, selectView>Show Sidebarfrom the Finder menu bar.

you might also use thekeyboard shortcutOption+Command+Sto toggle between viewing and hiding the sidebar.
The keyboard shortcut to show or hide the sidebar isOption+Command+S.
Depending on your version of macOS, this option may also be calledSettings.

you could also pressCommand+,(comma) on your keyboard.
InFinder Preferences, selectSidebarat the top of the screen.
Items in the Finder sidebar fall into four categories: Favorites, iCloud, Locations, or Tags.

Select or reset the check box, as appropriate, for each item in the list.
The items you check appear in the Finder sidebar until you change the preferences again.
Close theFinder Preferencesto preserve your choices.

A horizontal line appears, indicating the location the folder will occupy when you release the mouse button.
Release the mouse button to add the folder to the Finder sidebar.
The item remains in its original location.

you’ve got the option to create shortcuts to the applications you use most often, as well.
Position the system where you want it to appear and then release the mouse button.
To do so, drag the item to its new target location.

The other items in the sidebar rearrange themselves to make room for the item you’re moving.
It disappears in a puff of smoke.
Click and drag the cursor to move the dividing line and make the sidebar wider or narrower.
In Finder, locate the Google Drive app icon, then drag it into the sidebar.