Use validation rules to check if the data is in line with the defined standards.
To validate data, you can use these validation types:
Mandatory: Makes it mandatory to fill a field.
Blank: Validates if no value is entered in a field.
Range expression: Validates if a field value is within a defined range.
Data pattern: Validates if a field value matches a data pattern.
Web service: Validates if a field value matches a value in another internal or external source, using a web service.
Configurable lookup: Adds a custom lookup to a field and validates if the field value matches a value as defined by the configurable lookup.
Custom: Validates a field value using a custom validation class.
Query: Validates if an entered field value is allowed using a dynamic query.