Sometimes the form cannot be simple with few fields. Some data require you to build a long and complex form. In this case, it is always a good idea to group similar data fields by separating them with lines, spacing, or combining them with a border or background.
Usually it is best to group optional fields or vice versa the most important and required. In general, to separate with the help of grouping the primary from the secondary.
And, of course, it's always good to highlight the final action in a large form. It makes the form more convenient and understandable.
It is much easier for users to fill out a large form if it is divided into logical groups. Where each group has its own heading and sometimes an explanation of its fields.
By adding headings and explanations with grouping, it seems that we only make the form bigger. But there's nothing wrong with that. Splitting it up gives more consistency to the form fields and makes it easier for users to read bits and pieces of the form.
It is preferable never to make a form with several pages of steps. Such forms show the lowest conversion rate possible, cause the most fill-outs, and stress users out more often. People have other interesting things to do than fill out a multi-page form with endless steps.
Usually, the form is divided into steps because it's scary to show all the fields on one page at once. It seems that such a form will be complicated and confusing for the user. But there is no need to fear this. On the contrary, showing the entire form will give the user an understanding of all the required data and make filling out the form unambiguous and straightforward, and therefore only speeds up the process of filling out.
The easiest way to make the form easier to fill out is to have all the steps on one page at once. Users have no problem scrolling the page and it does not cause any troubles. On the contrary, such forms are always more effective and show the highest conversion rate.
Another way: make the steps expand as user fill out the form. Only still on one page.
Any form requires feedback, forgiveness of user mistakes and maximum predictability of any action. This is especially important for large and complex forms.
Users lose already entered data and experience the most difficulties in such forms. Sometimes they don't understand what can happen next and whether the data will be saved or not.
Do auto-save for large forms. Let users know that no data will be lost if they step back. Give the user control to see all further steps and safely return to the current step without fear of losing data.