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 below steps 

Step 1: Select Apps

Step 2: Select G Suite

Step 3: Select Google Vault

Step 4: Select the URL

Step 5: Click on Retention and Edit the Default retention rules for all items.

Step 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.

Done.