First off, a share in what? Is this assuming that, like most startups seeking investors, the company is formed as a Delaware corporation? Or do you want somet

First off, a share in what? Is this assuming that, like most startups seeking investors, the company is formed as a Delaware corporation? Or do you want something more along the lines of a partnership agreement, to use before any of the founders form an actual entity? The form of this agreement would heavily depend on the context.