How to set Google Vault to Indefinitely.
Visit the URL https://ediscovery.google.com/discovery/ and login with your Superadmin account.
OR Just Login to your superadmin account and follow image 1, 2, 3 and 4.
Image 1: Select Apps
Image 2: Select G Suite
Image 3: Select Google Vault
Image 4: Select the URL
Image 5: Click on Retention and Edit the Default retention rules for all items.
Image 6: Enable (tick) the Default rule settings for “Set a default retention rule for Mail/ Drive/ Groups”, and confirm the Duration to “Indefinitely” and save the changes.
Follow the same for Drive and Groups.