Securing your website is very important, especially if it deals with sensitive information.
To effectively protect your site, you should follow these tips:

1. Use Strong Passwords

-Avoid easy passwords.

-Use uppercase and lowercase letters, numbers, and special characters.

-Store passwords securely using:
password_hash() // to hash the password
password_verify() // to verify the password

2. Validate and Sanitize User Input

-Always make sure the data coming from users is clean and safe.

-Use:
filter_var() // to validate or sanitize input
htmlspecialchars() // to protect against XSS when displaying data
-And always use Prepared Statements when working with databases to protect against SQL Injection.

3. Use HTTPS

-Use:
session_start()
session_regenerate_id(true) // after user login
-Set secure cookie parameters:
session_set_cookie_params([
'httponly' => true,
'secure' => true,
'samesite' => 'Strict'
]);
-Also, log users out after a period of inactivity.

5. Keep PHP and Libraries Updated

-Always update your PHP version and any libraries or frameworks you are using.

6. Secure File Uploads

-Before allowing users to upload files:

-Restrict allowed file types (e.g., jpg, png, pdf).

-Randomly rename uploaded files using:
hash() // to generate a secure random file name
-Ideally, store uploaded files outside the public directory.

Conclusion

Security is an ongoing effort, not a one-time task.
By following these steps and using methods like password_hash, password_verify, filter_var, htmlspecialchars, hash, session_start, session_regenerate_id, and more, you can greatly protect your site against hacking attacks.