Go to Navigation pane > Modules > Organization administration > Organizations > Legal entities.
Click New.
In the Name field, type Fabrikam.
In the Company field, type FABR.
In the Country/region field, enter or select a value.
Click OK.
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/organization-administration/tasks/create-legal-entity?toc=/dynamics365/commerce/toc.json
https://docs.microsoft.com/en-us/learn/modules/plan-implement-legal-entities-finance-operations/2-create-legal-entity