The two types of read/write capacity modes are Provisioned, where you specify the needed capacity in advance, and On-demand, which scales automatically and charges per request.
The two types of read/write capacity modes for processing reads and writes on your tables are Provisioned and On-demand. In the Provisioned mode, you specify the number of reads and writes per second that you expect your application to require. AWS DynamoDB then reserves this capacity for your use, ensuring that your application doesn't exceed the limits and possibly incurring additional costs.
On the other hand, the On-demand mode offers a flexible pricing model where you pay per read and write request. This mode is suitable for workloads that are unpredictable or if you prefer not to manage capacity yourself. There is no need to specify capacity ahead of time, as the On-demand mode automatically scales to accommodate your workload.
Learn more about Read/Write Capacity Modes