Separate Anaconda installers are available for 32-bit OS and 64-bit OSes. Also, there are different installers for Python 2.7 and Python 3.7. The installer can be downloaded from https://www.anaconda.com/download/. The website would have the following options shown in the screenshot:
Anaconda installers for different platforms
Observe the following steps to install Anaconda on a Windows machine once the download is done.