“How to secure website” cannot address until we know the platform, web server, application framework, etc . So this is kind of generic question and you should expect generic answer only like SSL, firewall, WAF, web server hardening, application hardening, etc. So if you are on a shared server, leave those things with your host and choose a host who cares about security! if you are a beginner, I suggest going with Shared hosting as well. More important thing is to keep your application up-to-date, audit it regularly and make sure that no security hole is left. Always choose a strong password, create only necessary logins and advise the users to keep their password secure and change it periodically.