Help To Block Browser Extensions ..please advice using Defender ATP !

rathourshubham4  - You can use Endpoint Manager (Intune) to achieve this for various browsers:

Microsoft Edge: Use Security Baselines to configure the setting 'Control which extensions cannot be installed' - See https://docs.microsoft.com/en-us/mem/intune/protect/security-baseline-settings-edge?pivots=edge-sept-2020

Google Chrome: Use ADMX in Intune  - See https://support.google.com/chrome/a/answer/9102677?hl=en#zippy=%2Cstep-set-up-a-chrome-policy-with-intune

Mozilla Firefox - Use ADMX in Intune - See https://support.mozilla.org/en-US/kb/managing-firefox-intune