your category is real estate pro, so I am surprised that you are asking this question.
The laws, rules and regulations are different for every city, county and state. They can differ between incorporated areas and unincorporated areas a block away. You need to check with:
a) the local board of realtors that you belong to
b) ask your broker for the rules he will require you to follow if you are renting out your own property or handling rental property for others (determine if you are just handling the rental contracts and finding the renters or are managing the properties as well)
c) the local city gov
d) the local county gov
e) read up on the state laws on tenancy
f) if you intend to rent to section 8, make sure you contact the people running that office as well