Any person desiring to engage in the business of operating vehicles for the purpose set forth in § 111.30 of this code shall, before so operating those vehicles or engaging in that business, apply to the City Clerk for a license, and shall pay to the City Clerk at the time of making that application the sum specified by City Council resolution. The City Clerk, upon receipt of the application, shall forthwith refer the application to the Chief of Police for investigation that the applicant is a fit and proper person to conduct the business. No application shall be denied unless for just cause as shown by the investigation required in the processing of the application. Upon approval, the City Clerk shall issue a license under his or her hand and seal of the city to the applicant, which license shall be numbered. Before engaging in this business, the vehicle for which the license shall be obtained shall have displayed thereon in a prominent place a tag issued by the City Clerk for that vehicle. A separate license shall be necessary for each vehicle.