Not necessarily easy, but salesforce is the standard in tracking this type of information.
You can try to do it with a cheaper/ lighterweight CRM, but we outgrew two over the years (with a small catering company) to end up at salesforce this year.
You can use leads assigned to the rep against conversions to give the rep credit for their targets and track marketing campaigns using utm codes.
There are a ton of more limited/ specialized products (salesloft comes to mind) that tie to lead gen, but if this is a new pathway and you want flexibility/ customizability you'll probably end up at salesforce or save money with a knock-off like Zoho or SugarCRM
IF you can keep it all online, then hubspot may also be a reasonable alternative.