When you are using a long-form, you should use various methods to make a good user experience. For really long forms with many questions, here are several things that you can try:
1. Group your questions into sections
Sort your questions into manageable chunks. When you have a long-form, you are likely asking questions across many different themes. Your goal is to identify what these themes are and sort your questions into easy to understand sections.
Once you have sections this means that you can more clearly map where a person is in their process of completing the form. Completing sections also allows for small rewards in a long and likely not fun form filling process.
2. Make location visible
A key difference between short forms and long forms is that they require a different user experience. Short forms are filled out in a couple of minutes, long forms can take hours — and it is expected that people will take breaks between sessions. For long forms, you need to include a “you are here” feature, that keeps the person orientated while also giving the ability to estimate how much time is remaining.
To make the location visible, you want to show where the person filling out the form is in the process. You can use a percentage to complete icon, page numbers, bread-crumbs, loading bars, a stepper, etc. There is no standard go-to design for this, you’ll need to find a system that works with your form. In your case, I think this 2-levels tree indicator is fine.
3. Set expectations before the start
To prepare the person for starting the form, give them as much context as possible. This will increase completion rates for individuals that start the process.
Questions an introduction could answer are:
- Why is the person is filling out this form?
- How long should it take to fill out the form?
- What is the timeline for the next steps?
- Do they need to prepare anything in advance (e.g. have a driver's license handy or prepare documents)?
- What happens to the information they provide?
- Who has access to it, how will it be used, how does it meet privacy standards?
- Does filling out the form cost money?
- Don’t surprise people at the end with the cost.
4. Save each question automatically
When the user fills a long-form, some troubles might occur. Connection problems, session expiration, etc. Make sure that every step of the user is saved and he/she doesn't need to fill them again.
5. Don’t make questions out-of-focus
Only hide out-of-focus questions surrounding the in-focus question for very short forms. This design is good for a simple form like a survey but bad for long online forms with many questions.
When I fill out a form like this, I can feel my heart-rate rise because I’m trying to figure out if I’m being tricked into thinking the form is shorter than it really is.
This style of reducing the opacity for out-of-focus questions is not accessible. People will inevitably feel like they should read the out of focus text before it comes into focus. But, because the colors of the text on the screen do not meet contrast accessibility standards, the readability is reduced causing either difficulty for the person trying to read the out-of-focus question if they can even see it in the first place.