If you are planning to create a 15-question survey, that would be 15 fields. There might also be a few 'administrative' fields that
would not appear on the survey, but would appear to the survey administrator. For instance, maybe you want to include an 'admin'
field noting which survey results have been 'processed' and dealt with. This might involve adding a few other fields, like "processed? yes/no"
and "processed on ____ (date)". So this survey system might have 17 fields total.
Web applications (or web-apps) may also have non-functional (html) sections/areas. These are also considered to be fields.
For instance, if your survey has a preface statement describing the survey, then that section of text/html would be a field.
These "blank" areas may also be used for spacing/design purposes.
Another example might be a "Contact us" form/system for your customers to reach you via your website. To figure out how many "fields" this system
would need, just think of all the questions that you will ask the customer. See the first example below, and then compare it with the others.