How to add the CTI dialer
Add the CTI softphone utility to a Salesforce app so agents can make and receive calls from inside the platform, without leaving the record in view.
Step 1: Open App Manager
Go to Salesforce Setup, then use the Quick Find box to search for App Manager.

Step 2: Edit your app
Locate your target app and select Edit.
Step 3: Add the utility item
Navigate to the Utility Items tab, click Add Utility Item, and choose Open CTI Softphone.
Step 4: Configure the settings
Configure these settings:
Label: Enter preferred name
Panel Width: 360
Panel Height: 530
Start Automatically: Checked

Step 5: Save
Click Save to finalize the setup.