A customer record can be created by a request like this:
POST http://www.my-shop.com/odata/v1/Customers
{"CustomerGuid":"67ebb40a-fa3d-4243-a53b-6487f894847a","Username":"my@email.com","Email":"my@email.com","AdminComment":"","IsTaxExempt":false,"AffiliateId":0,"Active":true,"IsSystemAccount":false,"SystemName":null,"LastIpAddress":null,"CreatedOnUtc":"2020-10-12T10:00:00.913Z","LastLoginDateUtc":"2020-10-12T10:00:00.913Z","LastActivityDateUtc":"2020-10-12T10:00:00.913Z","Title":null,"FirstName":"John","LastName":"Doe","FullName":"John Doe","Company":"","CustomerNumber":null,"BirthDate":null,"Gender":null,"VatNumberStatusId":10,"TimeZoneId":"W. Europe Standard Time","TaxDisplayTypeId":0,"LastForumVisit":null,"LastUserAgent":null,"LastUserDeviceType":null}
Password data is stored in fields "Password", "PasswordFormatId" and "PasswordSalt" according to this
code. For security reasons this data is not transmitted via the API. You have to also provide a CustomerRoleMapping for the registered customer role. I have never tried to import password data via the API. The regular way would be to ask the customer to enter a new password instead of importing it.