Give the use for enabling knowledge user checkbox to any user

Hi @Rohit .

 The Knowledge User checkbox enables a user to work with Salesforce Knowledge. It is required for users who need to create, edit, publish, archive, or manage Knowledge articles, based on the permissions assigned to them.  

For example, Support Agents can use Knowledge to find and share articles with customers, while Knowledge Managers can create, update, and publish articles.  

The checkbox alone does not grant all Knowledge permissions; the required object permissions, field access, and permission sets must also be configured.  

Hope this Helps!!