In Field History Tracking we can select certain fields to track and display the field history in the History Related List. The History can be retained up to 18 Months. Whenever a certain fields are modified a new entry is added in the history related list. You can track field history for Custom and Standard objects.
Standard Object include: Accounts, Assets, Cases, Contacts, Entitlements, Service Contracts, Contract Line Items, Contracts, Leads, Opportunities, Articles, Solutions and Products.
Setup > Customize > Accounts > Fields
On Account Fields page click Set History Tracking
Currently the Field History Tracking is not active.
Enable Account History to track field history for account object. When we enable Account History following page is displayed.
Select the fields you want to track and save the changes.
On Account Fields page we have Track History column which shows fields selected for History Tracking. Add the Account History Related List to the page layout.
Account History related list was updated when the Account Name was modified. It displays date/time when the account name was modified, which user modified the account name and what was the action.
Setup > Create > Objects > (Select the Custom Object) >
Custom Fields & Relationships > Set History Tracking
Select the field to be tracked and save. Also add the history related list to the page layouts.