AWS offers many different database services that are fully managed and offer the same scalability, high reliability, and performance as their other cloud services. They offer relational, key-value, document, in-memory, graph, time series, and ledger databases. When AWS says their databases are fully managed it means they take care of things like provisioning servers, patching, setup, configuration, backups, and recovery. They also provide the ability to scale rather easily to meet your needs. You can start out small and as your database's compute and storage requirements grow it is pretty simple to provision more capacity without downtime.
AWS Database Services
Here is a quick breakdown of some of the most popular database services AWS offers.