On Linux platforms – create a blank text document and save it as .htaccess. Then upload it to your server using any FTP client.
On Windows – create a blank text document and save it as 1.htaccess. Then upload it to your server using any FTP client and rename the file as .htaccess
If the wordpress installation directory in your host is writable by WordPress, then it can create a .htaccess file if you change the URL structure in permalinks..