Is It possible to change label of standard field in user object?How?

Hi @MAADHINI NARAYANAKUMAR,

Thank you for reaching out to the community.

No, It's not possible for User object. For any other objects --->

Change a Standard Salesforce field

From Setup, enter Tab Names and Labels in the Quick Find box, then select Rename Tabs and Labels. In Select Language , select your default language. Click Edit next to the object containing the field label you want to change. 

 I hope this will helps you to resolve the issue.

Please feel free to let me know if you need further assistance on this.

Kindly ensure to mark this as best answer, if it solves your issue. This helps the community to consider this as reference & helps to avoid creating multiple questions on the same concept. 

Have a great day ahead!

Thanks & Regards

Nagarjuna