Can external users create sites inside a tenant

Rob_Elliottok thanks for the clear and useful reply. now i am working as a consultant for a client, so i though i can do this using my office 365 account then they can remove my access. so in this case, what they need is to create an internal user for me to do the work? what is the minimum license needed to be able to define the user as a SharePoint admin, my main work will be to create sites, lists, term stores and so on..