If iam resigning, can my manager not accept or does he have any influence to not allow it?

Manger can’t do anything, send mail to manger

No one can do anything with your resignation. Send resignation mail to HR keeping manager in CC. Enough.

This is your right noone can do anything, Nobody can make you work your not slave. Get any sample template from net and send to your manager cc your hr and in mail mention that you will be serving notice period of 90days starting from today. Hope it helps.

Resignation mail send to manager and keep HR in cc