With the subscription wide limit and per vault limit doubled, i.e. for secret GET and RSA 2,048-bit software keys, you'll receive 4,000 GET transactions per 10 seconds vs 2,000 per 10 seconds previously. The service quotas are specific to operation type and the entire list can be accessed in Azure Key Vault Service Limits. You can also view your Key Vault's usage on the 'Overview' page in the Azure portal on the "Monitoring" tab.
Learn more about Monitor Key Vault with Key Vault insights and monitoring metrics for Azure Key Vault.
There is no manual step required for increased service limits and this is by default applicable on all vaults without any additional cost.