You can send logs to Datadog in many ways. The Datadog agent (v6.0+) can tail log files, listen for logs over UDP/TCP, and collect logs from docker containers. For logs from AWS services, you can send them to Datadog by using Datadog's log collection lambda function.
Another option is to use common 3rd party log shippers to send your logs to Datadog, such as:
Learn more about how to send logs from other 3rd party log shippers from our documentation, or our log collection guides in your Datadog account here.