how make my default public ip to static ip in ec2 instance ?

To make your EC2 instance's public IP address static (permanent), you can associate an Elastic IP (EIP) with your instance.

Here you can find the documentation to learn how to do it.

Hi The way to do that is to assign Elastic IP address to your instance once it is created. You can allocate an Elastic IP address from Amazon's pool of public IPv4 addresses, or from a custom IP address pool that you have brought to your AWS account. if you have set the "Auto-assign public IP" to enable, then once you associate an Elastic IP address with an instance or its primary network interface, the instance's public IPv4 address (if it had one) is released back into Amazon's pool of public IPv4 addresses

https://repost.aws/knowledge-center/ec2-associate-static-public-ip