Shared hosting is, when multiple websites are hosted on the same server or on the same IP address. The alternative is when a server or an IP address is dedicated to a single website which is, dedicated hosting. These are usually common set ups.
Using shared hosting is perfectly fine and does not negatively affect your site in Google Search. Sometimes, when too many websites are hosted on a system with limited capacity, it can happen that the server is overloaded. This can result in the server and its websites becoming very slow. The same thing can happen with a dedicated hosting, though.