Each applicant is liable for all of the mortgage cost, although the lender assesses all applicants' income together.
Up to four people can be registered as a legal owner, in most cases, and you can create legal documents stipulating who owns what proportion of the property.
Most lenders will offer a mortgage based on a maximum of 4.5 times your combined annual income - although you can borrow five or even six times annual earnings in the right circumstances.