Hello @Nitesh, if this was the case few months or a year back you would have to call amazon and ask them to create a default vpc, thankfully they have given a descriptive way on how to create a default VPC here in this documentation.
https://docs.aws.amazon.com/vpc/latest/userguide/default-vpc.html#create-default-vpc
You can follow the link here. Do let me know as did it work for you or not?
I would let you know a substitute by which you would be able to create and access EC2 instances.
Hope it helps.