For different stages of a business, there is always a different type of investor for it. For instance, if you are at the startup stage, you may need a startup angel investor. In the initial stages, you cannot show patented equipment or technology that has a quantifiable or logical value, nor can you show a historical P&L. So, the company valuation here is based entirely on the founder’s vision for the company, along with the value of that market category or segment of the offering, the assessment of the market need, etc.
These kinds of angels who lead in the earlier stages usually demand a percentage of the company that they want in exchange for the funding they are offering. They would create a terms sheet that would permit you to earn or purchase all the equity back based on their terms.