The best place to download is the official Android Studio archive:
Since Iguana is an older stable release (replaced by newer versions like Koala, Ladybug, and Meerkat), you must download it from the official archive. Android Studio Iguana | 2023.2.1 (Feb 2024) android studio iguana download
After downloading, you can verify the file integrity. Example for Windows .exe (Iguana 2023.2.1.23): The best place to download is the official