The commissioner may adopt and enforce reasonable rules:

1. (a) Fixing the qualifications of licensees in addition to those prescribed in the chapter, necessary to promote and protect the public welfare.
2. (b) Carrying out generally the provisions of this chapter, including regulation of the conduct of licensees.
3. (c) For a change in the classification of a licensee, or in the type of business organization upon application therefore by a licensee, and to prescribe the fee, if any, to be paid.