How i can i add open login plugin button to notices in a way that we have Please " Login with twitter , log in or register"
This is only possibly with a core hack. You need to modify the function qa_insert_login_links from qa-app-format.php, which is in the core of Q2A and cannot be overridden by a plugin.
Have a look at this function here: https://github.com/q2a/question2answer/blob/master/qa-include/qa-app-format.php#L1018
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
April 20, 2021: Q2A 1.8.6 released!