A simple box in which you have the freedom to type. This may be formatted for words, letters or numbers only.
This is a larger text input area, often used for more comments. One way it differs from text input is that you can write paragraphs within the form, using the “return” key without submitting the form.
When you want to give certain choices to select from, pulldowns are used. Pulldowns are great when there are many choices (like the list of 50 states) to choose from.
Like the pulldown, you can have a set of choices shown. Radio buttons are good when there are not that many choices needed for an answer (maybe less than 20) and if you want the end users to see all of the choices. You can enable or disable a default selection for radio buttons.
When there is potential for multiple answers to a question, a checkbox form is helpful. Or when a website owner would like the end user to recognize and agree on a term or a condition, they ask you to mark the checkbox in agreement.
Captcha is a system that ensures form submissions are made by humans, not by machines. You may have been asked to type in a box a set of alpha numerals within an image, or asked to click an area of the image which is missing a piece. Often these are used to avoid spammers.
You can make a field in your form a requirement to fill out, such as asking for a name or email address. But you need to make sure you indicate that in the field clearly so people don’t get frustrated when they try to submit it without success.
Any and all forms should be constructed with the end user in mind. Difficult forms to fill out will be abandoned - and that is your loss, not theirs.