Difference-between-Profile-and-Permission-Set

 Profile: 

Profile is a group/collection of settings and permissions that define what a user can do in Salesforce. A profile controls “Object permissions, Field permissions, User permissions, Tab settings, App settings, Apex class access, Visualforce page access, Page layouts, Record Types, Login hours & Login IP ranges.

You can define profiles by user’s job function. For example System Administrator, Developer, Sales Representative.

A profile can be assigned to many users, but a user can be assigned a single profile at a time

Permission Set: 

The permission set is also very similar to profile. Whatever you can manage at profiles (Like Object permissions, Field Permissions, User permissions, Tab settings, App settings, Apex class permission, visualforce permission) the same you can manage here also. 

But the main difference between these two is that user can have only one profile and can have multiple permission sets at a time.

So we can define profiles to grant minimum permissions and settings that every type of user needs, then we can use permission set to grant additional access.

Examples: 

1. We have many users in your organization with some fundamental job functions. We can assign all of then with one profile that grants them all access to do their job. But some set of people are working on special apps or some special functionality, for this type of special user we can create permission sets and can be assigned to them.