Torrent is a file that contains various information and BitTorrent metadata from a file to be downloaded. Some metadata information in the torrent file such as announces that contain the URL tracker list, name and info piece that contains information about the file name, folder and the number of bytes for each part of the file, pieces info that lists the file hashes. You could also find info length that contains the duration of a file, file path info that contains information from the path or location of files and folders and file, and file length info about the information about the total file size.
If the file you are about to download is likened to a location, then the torrent file is a map to get to that location. All information and metadata contained in this torrent file will be used as a reference by the BitTorrent Client to download (as well as an upload) the files you want. So if you download a file through BitTorrent, then you download it from various other people’s computers that are also (or have already) downloaded it. At the same time, your computer is also a source for other people to download the file.