I'm creating a custom profile page and I want to save some information in a custom object in Salesforce. How would I go about doing this? I assume I would be using SSJS rather than AMPscript. Thanks in advance, appreciate any pointers.
AMPscript would definitely be the way to go, assuming you have Marketing Cloud Connect configured. There are different AMPscript functions for creating and updating records in standard or custom objects.
Create New Record
var @createRecord set @createRecord = CreateSalesforceObject( "MyCustomObjectApiName__c", 3, "field1__c", @field1, "field2__c", @field2, "field3__c", @field3 )
Update Existing Record
var @updateRecord set @updateRecord = UpdateSingleSalesforceObject( "MyCustomObjectApiName__c", @Id, "field1__c", @field1, "field2__c", @field2, "field3__c", @field3 )
Refer to Sales and Service Cloud functions documentation for details on which arguments to use with these functions.