You can watch the movie Conclave on Amazon Prime Video, where it is available to stream for free with a Prime membership in the US, UK, and many other countries

. It is also available to rent or buy digitally on platforms such as Apple TV, Sky Store, Fandango At Home, Microsoft Store, and others, with rental prices around £4.99 to £5.99 and purchase prices around £9.99 to £19.99 depending on the platform and region

. In summary:

• Streaming included with Amazon Prime Video subscription (US, UK, and more)
• Rent or buy on Apple TV, Sky Store, Amazon Video, and other digital stores

This makes Prime Video the most convenient option if you have a subscription, while digital rental or purchase is available if you do not.