The complicated answer is really a UX issue. Often developers and business owners ask for way too much information at the start, almost always not needed.
There are many UX tricks to reduce the info needed or the perceived amount needed and therefore give the ability to condense the application / form down to a single page.
Remember back in the day when you would sign up to a news letter and they asked everything from company size and $ to gender? … not it’s just email only.