I came across a TAB in the F5 which talks about AWS.
Main --> System --> Configuration --> AWS.
This has a access key and a secret key to enter.
what is this used for? Is it for some integration between the F5 and the AWS?
or is this only for F5 instances deployed on the cloud?
This is used when deploying F5 devices in AWS. Specifically on page 9 of this deployment guide, you can see that it is needed for Advanced HA across AWS Availability Zones (AZs) since normal High Availability configurations are not possible across AWS AZs.