How to fix "Headers already sent" error in PHP

Hi everyone! I'm a beginner in PHP and encountered a very annoying error. I'm writing a simple script for redirecting a user after authorization, but I get this message:\n\nWarning: Cannot modify header information - headers already sent by (output started at /home/user/index.php:10)\n\nHere's my code:\n\n```php\n\n\n\n\n

\n \n \n Login\n

\n \n\n```\n\nI understand that the error is related to headers already being sent,