I use JIRA function "Creating Issues and Comments from Email". And i wont Assignee issue to some user, i add him in field CC: in email like in manual https://confluence.atlassian.com/jira/creating-issues-and-comments-from-email-185729464.html but when issue created in field Assignee i see the user which was in field TO: in email.
How fix it ?
Fix what? You've described what is happening (which is what the docs say it should do), but not what you want it to do.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.