It's very easy to sign out of Dropbox, either from the application installed on your Mac or PC, or by using the Dropbox.com website.
Steps
Method 1 of 3: Sign out of Dropbox on macOS
Step 1. Click the Dropbox icon in the menu bar
It represents an open cardboard box and is located in the upper right corner of the screen.
Step 2. Select Account
This icon represents the silhouette of a person.
Step 3. Choose Unlink this Dropbox
This will sign you out of Dropbox. A login window will appear in case you want to log into another account.
To sign in to Dropbox again, click the Dropbox icon, then sign in to your account
Method 2 of 3: Sign out of Dropbox on Windows
Step 1. Click the Dropbox icon on the taskbar
It is usually located in the lower right corner of the screen, near the clock. Look for the blue and white open cardboard box icon.
If you can't find it, click the up arrow. A menu with other icons will appear
Step 2. Click the gear icon in the Dropbox window
A menu will appear.
Step 3. Choose Preferences…
Step 4. Select Account
This is the second icon from the left towards the top of the window.
Step 5. Choose Unlink this Dropbox
This will sign you out of Dropbox. A login window will appear in case you want to log into another account.
To sign in to Dropbox again, click the Dropbox icon, then sign in to your account
Method 3 of 3: Sign out of Dropbox.com
Step 1. Go to Dropbox in your web browser
The contents of your Dropbox should appear on the screen.
Step 2. Click on your profile picture
It is located at the top right of the page. A drop-down menu will appear.
Step 3. Select Sign Out
You are now signed out of your Dropbox account.