If your business is required to document the Applicator License number for your technicians, you can do this for an Employee or Vendor. This number will appear on the Chemical Tracking Report for Services completed by each Resource.
For an Employee, got to Team > Employees. Click on the name of the Employee you need to modify and then click the Edit link. The Applicator License field will be on the "Personal Information" tab:
For Vendors, go to Team > Vendors. Click on the name of the Vendor you need to modify and then click the Edit link. The Applicator License field will be on the "Employment" tab: