1. Fixed Price
This contract specifies business and technical requirements, product release date, and the overall cost. Since the key priority is to meet these terms, it’s very important to prevent various issues - extra work, prolonged stage approval process, etc.—that may lead to delivery delays and budget overrun.
Therefore, correct estimation and task planning are critical elements of success. So, define the app/website goal, prepare a detailed technical specification, create mockups and wireframes.
As it’s difficult to do without specific background, consult IT experts: business analysts, project managers, engineers specializing in the necessary field (if you need, for instance, a blockchain solution for an insurance firm, turn to a custom blockchain development company that has already helped underwriters accomplish their business objectives).