This is a note from the guy that wrote the support article on blocking a sender more than a decade ago telling folk how to do it with a filter. https://support.mozilla.org/en-US/kb/blocking-sender

Please post your ideas and feedback in the ideas and feedback forum. It is linked from the Thunderbird help menu as it this one. Blocking a sender may be important to you. I can't really think of anything worse in business that a one click block to creditors sending accounts.

Thanks for this. I have seen that aption. However it is much better to have option to block unwanter sender rather rediecting messages to spam or other folders and get them accumulated in email forders. Other email clients provide this option. I ask Thunderbird team to kindly get this in thunderbird. Thanks