In normal case your customers create account themselves through the customer registration page without need for you in the middle. However, there are special cases in which for one reason or another the customer registration is not a match and you should create accounts manually.
Manual customer creation happens in the main view of Customers page, where you can select whether to add one customer or import many.
If you have only one account to be created, just head to Add one and fill in the customer details. When creating the customer you can define the customer type (prepaid/postpaid) and give her an access also to selected private charging points if needed. You can also define on if and how they receive notification of an account created to them together with the credentials. Once the customer account has been created, you can briefly see the credentials to share with the customer.
If you would like to create a bunch of new customer accounts at once, you can use the import many functionality. For that purpose you need the csv file which you can find here. Fill in the csv file following the example and save it to you computer. In Import many just select the file from your computer, pick the EMP organization from the list and import customers. After the import you can see the credentials of the created customers to be shared with your customers.