I would like to know if there is way in Marketing cloud through code/clicks to send an email to a specific user(s)[Admins] when user is created in Marketing cloud .
As far as I know, there is no UI way of doing it. It might be a quite complex implementation, that is why there will not be everything prepared for you but here is the idea of what you can do:
Create an Automation, which would run every day/hour (depends on how frequent you want to check for new users);
Add Script activity that would perform SOAP API call via SSJS. You can check this example;
2.1 API call would do a Retrieve method on AccountUser object with some filters on
CreatedDateproperty. You would probably need to set a variable date rather than a hardcoded one. Example of SOAP API call and filtering;
2.2 In the response body, you would receive all users that have been created based on your filtering date. Parse the response body to get all the needed info about newly created users;
2.3 This step could be done differently, for example, you can put parsed info into Data Extension with Overwrite data action;
And add Email activity to the automation, which would have AMPscript to lookup into the Data Extension and pull all the data and finally send it to your admins.
Not saying this is the perfect suggestion, there is definitely room for improvement, since you can actually do everything within one Script activity but that is going to be up to you. Hopefully, it helps.