This is a quick question. Is it possible to create custom Object in Salesforce Essential Edition?
If so, is there a way to enable it?
If you look at the Salesforce Help doc on creating a custom object, you can see that Essentials is not supported
REQUIRED EDITIONS AND USER PERMISSIONS
Available in: Lightning Experience
Available in: Contact Manager, Group, Professional, Enterprise, Performance, Unlimited, and Developer Editions
You need to upgrade to one of those editions.