If you have a legit MSDN subscription, the key is visible on the same download page. For retail keys, check your email or original packaging. No crack/pirated keys are ever recommended.
Microsoft maintains an archive of older software via their Visual Studio "Older Downloads" section. You will likely need a free Microsoft Account (Outlook, Hotmail, etc.) to access visual studio 2012 download windows 10
: Access the download at My.VisualStudio.com . If you have a legit MSDN subscription, the
Select (not “Custom” unless you want to remove SQL Server or SDKs). visual studio 2012 download windows 10