The evaluation is kept confidential, but the editor uses it to decide whether or not to accept the article. The editor may reject the paper, accept it, or send it back to the authors to be revised according to the comments of the reviewers, whose names are never revealed. The author must then revise it and resubmit it. It is then typically sent back to the same reviewers for review again. This entire process may be repeated again.
Some editors also look carefully at the bibliography.
If it is poorly formatted, with numerous mistakes and typographical errors, they may take this as a sign that the scientific work was likewise poorly done. It is better to make a good impression from the very first contact. You would not go to an important business meeting to meet someone for the first time wearing dirty clothes. The same principle applies here. If an article is sent back to the author by the editor requesting that the English be corrected, this should, of course, be done before resubmission, however, it cannot be guaranteed that it would then be accepted.