How to change the name of Standard objects (Standard Object Tabs) and Standard Fields?

How to change the name of Standard objects (Standard Object Tabs) and Standard Fields?

HOW TO CHANGE STANDARD FIELD LABELS

A Salesforce field has three parts in its name - the Field Name which is the unique name of the field (for example, FirstName, or Custom_Field) the Label, which is what users see on a page layout (for example, First Name or Custom Field) and the API Name which you would reference in integrations or formulas (for example, FirstName or Custom_Field__c). It's not advisable (and often not possible) to change the Field Name or API Name, but changing a Field Label is trivial and can often improve user adoption with little impact on functionality.

How you can tell that a field came from a Managed Package. Look for the icon and the fact that there's a defined Namespace (that will become part of the API Name)

Field Label - what appears on page layouts for users to see

Field Name - the unique name which has no spaces or special characters

Field API Name - the integration name, which is the namespace prefix, followed by the complete Field Name and __c (to mean it's a custom field)