Collection Field

Collection field represents multiple values field whose values are made by using several other columns values. Each value of each combined column will be used as collection of values for this field.

 Here are the Options for Collection Field:

Name - Name of the Field you are creating

Type - Type of field ( In this case it can only be Collection as it is a Collection Field) 

Combine Column - Columns you will combine to get the collection of fields

Note: If you select fields from multiple collection fields, collection from last selected field will be used as source data.

This Custom field is the same as combined field the only difference is that we use it for "collection" fields.