Do I need to modify program code to install an SSL certificate?

Installing an SSL certificate does not require modifying program code.

It mainly involves server configuration (such as Nginx/Apache settings or operations on the cloud platform console).

However, if there are hardcoded HTTP resource links (such as images and scripts) inside the website, you need to manually adjust them to HTTPS to avoid mixed content warnings. This is not part of the certificate installation itself, but falls into the category of content optimization.