Question

how I can  know who sent the vote?

and any post user sent vote

Answer 1

Unless you have access to the database, you can't. This is a feature.

If you have access to the database you can see who voted on which post in the table qa_uservotes.

Answer 2

You can see who voted by hovering your mouse over the number in the vote box (e.g. +1).

There is a setting in Admin > Permissions to control which level of users can see it, by default it’s moderators and above.

(If you mean seeing it on this site, or any site you’re not a member of, you can’t.)