Entitlements and Milestones help the team keep track of which cases need immediate attention by defining appropriate service levels and outlining steps within a service process. With customers expecting outstanding customer service, want to meet their expanding needs. Entitlements can be related to Accounts, Assets, Cases, and Service contracts.

                   They could also be related to Contacts in Classic only but that feature is not available in the Lightning Experience. Milestones represent required, time-dependent steps in the support process, like a first response or case resolution times. 

Enable Entitlements

                The first thing have to do before using Entitlements is actually enable them! In Setup →  Service →  Entitlement Management → Entitlement Settings check “Enable Entitlement Management” and Save.

Set Up Milestones

To configure Milestones, navigate to Setup →  Service → Entitlement Management →  Milestones. Select the New Milestone button, give Milestone a name, and then select the Recurrence Type. There are three options for recurrence types. Here’s a little more about each one:

• No Recurrence
  • It will only occur once in the process.
  • Example: Initial Response
• Sequential
  • They occur regularly until the process is ended.
  • Example: Provide Customer with Update
• Independent
  • They occur independently of other milestones when certain criteria are met
  • Example: Solution Proposed

Create an Entitlement Process

                Navigate to Setup →  Service →  Entitlement Management →  Entitlement Processes. Create a new Entitlement Process and pick the object want to link it to. Typically the defaults will work, but if have special customization that needs to leverage then the other options may apply. Entitlement Process Business Hours define when the Entitlement applies and will drive when Milestone countdowns are running vs. paused unless the milestone has its own business hours assigned.

Add Milestones to Process

• Entitlement Process: starts the milestone countdown when the process first starts.

• Milestone Criteria: This allows the creation of specific criteria that trigger the start of the milestone. For example, the status moving from “Waiting on Customer” to “In Progress” could trigger a “Provide Customer with Update” milestone countdown to ensure frequent customer communication is happening.

In addition to the list of Milestones on the Entitlement Process detail page, Salesforce also generates a visual.

Add Workflow Actions to the Process Milestones

    There are three categories of Milestone Actions depending on when they want them to fire:

• Success Actions:

             The actions to take when a milestone successfully completed. Success actions still fire on milestones that are completed late.

• Warning Actions:

             The actions to take when a milestone is near violation.

• Violation Actions:

              These actions fire when a Milestone is violated (the countdown is over and the Milestone is still open).

Configuring these Workflow Actions works pretty much like any other workflows and time-based workflows in Salesforce.

For more blogs: How to Use Send List Email Button in Salesforce Lightning

Reference from: click here