There can be certain situations where you want to create a new customer account manually and not have the account created via the signup URL.
In this situation, you would need to click on the Customer's tab (ref. 1.) on your partner portal.
Find and click on the "Add" (ref. 3.) button. On the right-side panel, you will see that a newly generated account will be displayed.
You will need to fill in all the required information (ref. 4.) and then click on "Create" to save the changes.
Note: When the customer account is created under the 30-day free trial, a credit will be applied to the customer account balance.