Disabled WP-Admin using a php code

Access your site via FTP, find the file you edited, and comment out the code you added the broke the site.

Could you explain how i could access my ftp, i am a newbie.

use a tool like filezilla to access your hosted files via FTP. Contact your host for FTP configuration details.

Also, NEVER EVER EVER (ever!) use appearance->editor to modify PHP files. One slip and your site is dead. Download files, save a copy for safety, edit locally, and upload the changes.

Thank you very much, i will try that right now.

Thanks alot, i just tried that and it worked. Thank you.