Each time we are creating EC2 instance , Can we edit the same instance and overwrite the bootstrap script to run as different instance or the instance cannot be edited later ?
I’m not really sure what you’re trying to achieve.
Rather than manually updating and installing software on a newly-created instance, do you want to include everything in user-data?
You might want to simply store the user-data script offline and update/version as needed. You may also want to look at creating a standard AMI that you can launch with. Similarly, Launch Templates can be created to launch your instances and CloudFormation stacks can be created too if you really want overkill. All are part of SAA so any exposure to them would be of benefit.