This will also involve taking proper, considered advice, from your accountant or tax advisor.
From a legal perspective, we generally dissuade business owners from trading in their own name (i.e. as a sole trader) or trading as a partnership of individuals. The reason is no limitation of liability for the individuals. If the business becomes insolvent or there are unexpected claims not covered by insurance, then assets that are personally held may be at risk from creditors.
The right structure may be a company but consideration needs to be given to the right entity to hold the shares. Shares held by a discretionary trust with a corporate trustee may work better for asset protection and tax planning purposes than shares held in your own name.
Also, classes of shares may be an option where you have one shareholder who is not investing cash but “sweat equity” for the venture. The class of shares could be a converting redeemable preference share that converts to ordinary shares once the agreed “sweat equity” milestones have been reached.