Limited Liability Partnership
The key difference between a limited liability partnership (LLP) and a standard partnership is that each partner will have lower liability for any debts that the business might incur. Each partner will still register themselves as self employed and complete annual self assessment forms, however in addition to this; partners will need to file an annual partnership tax return.
To become incorporated you would need to notify Companies House and fill in an incorporation application form. Companies House will charge around £20 to set up a limited liability partnership , however you may want to get your lawyer or accountant to do it for you which will of course cost you extra.
At the time of formation you will also need to draw up a "Deed of Partnership", this is a legally binding agreement between members which lays out the rights and responsibilities of each partner. This will also detail how much capital each member has invested into the business and what would happen if one of the partner leaves.