we have an adobe campaign instance where we want to test the consistency of email delivery across different email clients. I believe our subscription with Adobe Campaign already includes Litmus. My challenge is how can I integrate Litmus with Adobe campaign so that we can test our delivery across different email clients and platforms before sending.
Inbox Rendering option (optional module under license) was made with home-made technology before build indicated by Shefali, so you can use it if you can't upgrade your Adobe Campaign version. In that case, you must read the former documentation of Adobe Campaign for former Inbox Rendering mechanism.
But I strongly recommends to upgrade regularly your AC instance to get newer builds. It helps to improve useability and being ready to new behaviors/new functionalities. And it helps community people to answer you easierly. Not to mention that it helps Adobe Campaign support to answer you quicker and better.