There is no ISO available to download for VS2017. You can view why Microsoft did not make ISO available, is discussed in here. However if you want to download VS 2017 to perform an offline installation you can follow the steps described below.
- Download the relevant VS installation .exe (for example vs_enterprise__984310617.1489458965.exe).
- Copy it to your local hard drive folder let’s say E:\Install
- Create a folder to download installation files say E:\Install\VS2017 (can be in a different path such as D:\VS2017)
- Open command prompt as administrator and change the directory to where your downloaded .exe is available
- Execute the command below