Upvote:4
Both you AND your sponsor should include everything that you, the applicant, must include, including evidence of property ownership and permission to lodge guests, as appropriate or required.
The documents, all of them, should be presented in your bundle at the time that you submit them, and the UK Visas & Immigration supporting documents guide lists what is required.
As you prepare your application, it may be helpful for you to review the content regarding sponsorship, contained within the comprehensive overview of UK visa refusal on V 4.2 a + c (and sometimes 'e').
As noted, it can be risky to rely solely on documents provided by a sponsor. A 'friend' offering complete support for two people for a two-week visit raises questions, and considerably raises the bar for the applicant. Sponsorship does not relieve the applicant of providing substantial proof of their ability to qualify for a visa. Indeed, having, or needing, a sponsor has been shown to increase the burden on the applicant to demonstrate that they qualify, independently.