Just follow these steps to backup WordPress Site to Dropbox with UpdraftPlus Free Version!
In this post
Step 1. UpdraftPlus Settings
Settings > UpdraftPlus Backups > Settings > Click on Dropbox Icon
Scroll down and click on Save Changes
Then, click on
Log in to Dropbox Account
Click on Complete Setup
and you will see
Step 2. Backup WordPress Site to Dropbox
Settings > UpdraftPlus Backups > Backup/Restore > Backup Now
Check on Send this backup to remote storage
In-Progress…
Done!
and Here is the Backup file
In Dropbox