jbinbpt coment was not quite correct, he should of said you should place the robots.txt file in the root directory of your website which is the same place as your index.html file, you can have html files in other directories.
A robots.txt file will not help to get your site indexed in a search engine, this file is only used to disallow robots not to allow, and thats only if the spider or robot what may visit is a friendly robot, if its not it will just ignore the file and spider your site anyway
Hello ncw164x The problem with my site is that, it is finished now and the major index.html file is not in the root directory. I started my site with good google position 4-th place from 512000 sites. But after that i renew information on my site - meta tags, title etc...I use in one technique in my site- when i upload pictures in it, the script automatically give to the alt tags of the pictures good keywords. can it be the problem with indexing by Googlebot. When my index.html is not in root directory, how i must submit in the search engines-with the full path to the index.html or only to the root directory. Do you know someone who will help me. Even i can pay for supporting of my site and for increasing its rank popularity 10x in advance ps. can you give me an E-mail of the google support centre to write to them, because it is really important for me and my work