From a licensing perspective, Dynamics 365 saw a departure from the familiar essential, basic, professional, and enterprises licenses to a team member, application-based, or plan-based licensing model.
Team member licenses are equivalent to essential licenses in previous Dynamics CRM versions. Team member licenses only offer read-write to account, contact, custom entities, and a few other supporting capabilities. However, most of the remaining out-of-the-box entities can only be accessed in read-only mode.
The following extract from the licensing guide highlights the different access types based on the different license types:

Whereas this screenshot highlights the different types of usages...