What type of monitoring file is commonly used on and accepted from Internet sites?

What type of monitoring file is commonly used on and accepted from Internet sites?

انٹرنیٹ سائٹوں سے عام طور پر کس قسم کی نگرانی کی فائل استعمال کی جاتی ہے اور اسے قبول کیا جاتا ہے؟
Explanation

Cookies are small files stored on a user's device by websites to track activity, preferences, and login information.

They are commonly used and accepted for monitoring user behavior on the internet.