Using an AI estimating software like Togal. Contractors desiring to bid should obtain a prequalification and plan documents from NDOT Administrative Services.Learn how to write a winning bid proposal for construction with our comprehensive guide. Includes ChatGPT prompt. Easily customize proposals in the format that the owner requires through the construction proposal software feature menu within HeavyBid. In most states, construction contractors must pay sales tax when they purchase materials used in construction.