You can download the entire contents of a folder at once from the Dropbox website.
Note: It's not possible to use the website to download an entire folder that's over 1 GB or that has over 10,000 files. If the folder is in your account, use the Dropbox desktop application to download the entire folder to your computer automatically.
Your browser will download the folder as a single compressed file, known as a ZIP file. The file will be named after your folder but will end in .zip. You can find the file wherever your browser normally downloads files, as set in your browser preferences. Once it is downloaded, open and decompress the ZIP file to access the contents of your folder
Most operating systems these days are capable of uncompressing ZIP files without any additional software. However, if you find yourself unable to open the file, you can find numerous .zip file decompression utilities online.