In AWS, you need Access Key ID and Secret Access Key to call AWS functions. If you don't have access keys, you can create them by using the IAM console at https://console.aws.amazon.com/iam/
Followings are the process to get your access key ID and secret access key:
Open the IAM console at https://console.aws.amazon.com/iam/
→ Navigation Menu → Users → Choose your IAM user name → Open the Security credentials tab
→ Choose Create access key
→ To download the key pair, choose Download .csv file. Store the .csv file with keys in a secure location