It supports HTTP, HTTPS, and FTP protocols, and retrieval through HTTP proxies. wget is non-interactive, meaning that it can work in the background, while the user is not logged on, which allows you to start a retrieval and disconnect from the system, letting wget finish the work.

Does wget use TCP or UDP?

It supports HTTP, HTTPS, and FTP protocols, as well as retrieval through HTTP proxies. HTTP, HTTPS, and FTP are all TCP protocols (and respectively use default TCP ports 80, 443, and 20/21). Therefore the answer to your question is: wget uses TCP. Any source that could have said that wget uses UDP is plain wrong.

Does wget use FTP?

Wget is a computer tool created by the GNU Project. You can use it to retrieve content and files from various web servers. The name is a combination of World Wide Web and the word get. It supports downloads via FTP, SFTP, HTTP, and HTTPS.