If you want your store to only be visited by people you want, not general public, you can easily set up a private store with Miiduu. 

To set the private status, go to your Miiduu store administration->"Settings"->"General"->"Advanced"->"Private Store", check 'Yes' and then 'Save'.

Now all your store visitors can only visit your store by registering an account or logging into their accounts on your site.

You can control the registered accounts visiting your store by approving them on your site.
To approve the accounts, go to "Sales"->"Customers". Click on the "Approve" icon to approve customers. Then only 'Approved' members can visit your store when they login to their accounts.

You can also prevent the approved accounts from visiting your site by editing the customers. Go to "Sales"->"Customers". Click on the "Edit" icon. Change the "Status" to "Disabled". 

*Please note that this feature is only available for business plan accounts.