Fields are coming from the same page layout related list fields configurations. Like go to Edit Page -> Account Layout which is applicable for the current User/RT (you can see the name of the assigned layout on flexi page) -> go to Layout -> click on Related list -> and configure the fields to be displayed under quick links related list here.
Create an Apex controller for your page and set DML options for insert:
Database.DMLOptions optionsForInsert = new Database.DMLOptions();
optionsForInsert.DuplicateRuleHeader.AllowSave = true;
List<Database.SaveResult> ans = Database.insert(toInsertList, optionsForInsert);
The problem lies in your Apex class. You were getting the system.stringException. See the image below. It is because you were assigning a string value to ID type field in your apex method(Id result = '';). So when your trying to assign an empty value for Id field we have to specify null keyword instead of an empty space('')
Replace your apex method with ...