What the franchisor will or will not do is set out in the franchise agreement and so you need to have a very clear idea from the franchisor before you sign the franchise agreement precisely what it is that you will receive for the initial fee that you are paying.
Usually franchisors require franchisees to undertake shop fitting themselves at their own cost, but in that case, almost certainly you will have to comply with the designs prepared by the franchisor because it would be unusual, and worrying, if the franchisor gave its franchisees a free hand to design their own retail premises.
In many cases you will also have to make use of the franchisor’s nominated shop fitters and if you do there should be a provision to require the franchisor to ensure that those shop fitting services are provided as economically as possible.
If the franchisor is undertaking the shop fitting then the initial fee that you pay will cover the costs of doing so. This means that either way you will be paying for the shopfit! If you are buying an existing franchise business and that business’ retail premises comply with the franchisor’s current requirements you will not have to undertake any shop fitting.