Can we have a roll up summary field in case of lookup relationship in Salesforce?

Hi Prachi,

Yes, You can have a roll-up summary field in case of lookup relationship in Salesforce. You can create rollup summary fields on the master record to summarize the detail records. The relationship field allows users to click on a lookup icon to select a value from a popup list. The master object is the source of the values in the list. Creates a relationship that links this object to another object.