A shareholder is a person who owns a share of a company. A shareholder has certain rights that are defined by company law in your jurisdiction and the Articles of Association or Constitution of your company. Typically, these rights include the right to receive dividends from the company, the right to vote at a general meeting, and the right to receive a return of capital if the company is liquidated.
A "founder" is commonly understood as the "entrepreneur who started the business". Legally speaking, the founder is "the first shareholder" of a company. A founder has exactly the same rights as a shareholder (if they hold the same class of shares).
To govern the relationship between the founders and shareholders of a company (e.g. restrictions on transfer of shares or consents required for decision-making), you need a Shareholders' Agreement or a Founders' Agreement. On our app, these two documents give you the same protection and obligations; it's only a choice of your preferred terminology.
Our Document Builder will ask you to identify the shareholders or founders and they will be listed out in Schedule 1 of the document in the form shown below:
Note, however, in a Seed Investment Agreement (Ordinary Shares), an agreement under which investors give the company funding and get ordinary shares in the company in return, the pre-existing shareholders are referred to as "founders" and the incoming shareholders are referred to as "investors". These are just names that are given to the parties to identify them with their respective rights and obligations. After completion of the funding, all "founders" and "investors" will be shareholders of the company.
Some people may confuse a Founders' Agreement with a Co-founder Agreement, which in substance is a Share Vesting Agreement under which the company gives shares to a co-founder that are subject to the company's buyback right.