A request may include multiple questions, each from one of those types. 

Free text

A free text question means that the honswerer may answer whatever they want. It can be a single word or multiple paragraphs. 

Since it requires more effort and imagination from the honswerer it is the type of question whose answers elicit grading from the requester. 

It is relevant when you expect complex thoughts and comments and don't want to limit the range of possible answers.

Rating

A rating question allows the honswerer to select a value between 1 and 5. 

It is relevant when you expect answers regarding a measurable element. The request report will calculate and display (for your eyes only) the average score for each of the rating questions your request includes.  

Options

An options question allows the honswerer to select an among a list of predefined values. You'll have to supply the possible options. For instance: "Improbable", "Probable", "Likely", "Certain", etc.  

It is relevant when the range of possible answers is limited. The request report will compute and display (for your eyes only) the number of times that each options was selected for each of the options questions your request includes.  

Number

A number question allows the honswerer to type in a numerical value as an answer.

It is relevant when you want to know about a numbered value, like "how much would you be willing to pay for...", "how many years should I wait before...". The request report will compute and display (for your eyes only) the an histogram of the provided answers for each of the numbers questions your request includes.