Does it matter for the SEO if my website is placed in subfolders?
Websites are typically structured either in subfolders or subdomains. Using a subfolder structure is better for SEO, because every page is underneath your domain name, thus your website links will increase. By having your website set up with a subdomain structure, if your internal links are not set properly it would get no value from the main domain name, which is not a recommended SEO practice.
However, the actual location of a webpage is not taken into deep consideration by search engine bots. What is important is how easy it is to reach that page via links of your website – the more a certain page is linked on other pages on your website, the more important it is considered to be.