An SSL certificate is a type of digital certificate that provides authentication for a website and enables an encrypted connection. These certificates communicate to the client that the web service host demonstrated ownership of the domain to the certificate authority at the time of certificate issuance.
If you don’t have an SSL Certificate, your website may still function as always, but it will be vulnerable to hackers and Google will warn visitors that your website is not secure.
Google also gives priority to websites that have an SSL certificate. So, you will eventually lose your position on Google’s search results to competitors who have SSL certificates.