There may be instances where you do not want your users creating records using this form. The default behavior fort Accounts, Contacts, Opportunities, and Leads is to allow Quick Create. To turn this off, System Administrators can navigate to:
Settings ==>Customizations ==> Customize the System
Click on the entity name, in this example it's the Opportunity entity. Then simply uncheck "Allow quick create":
Save, Publish, and you're all set!