Analyze and report on permission assignments with the User Access and Permissions Assistant. Manage your permission set groups easily, and convert to permission sets that you can assign. Previously, this feature was known as Permissions Helper.
Where: This change applies to Lightning Experience and Salesforce Classic in all editions.
How: To use this feature, download the app from AppExchange. Complete the tasks to enable the Tooling API for the app. And then create and assign permission sets for users who must access the app.
Manage Your Permission Assignments with the User Access and Permissions Assistant (salesforce.com)