how many account i can have with license basic (Free)

Hi @Andrcueg 

Welcome to Zoom community. Is the Principal account a licensed account ? And are you trying to add Basic Licenses Zoom phone users or Zoom meetings users ? If the principal account is  Licensed  for meetings or phone , you will be able to add more Basic accounts for either Phone or Meetings. 

Here is a good KB which explains the difference:

https://support.zoom.us/hc/en-us/articles/201363173-Zoom-user-types-roles

Hope that helps