Question on General Visit visa

Hello,

I am planning to invite my parents to UK on a General Visit visa as my current visa is limited to 5 years.

I intend to call my parents for 3 months.

I have all the documents apart from lease agreement. I don't have this document, can I still apply for "General visit visa"? Are their any chances of visa getting refused if no lease agreement is submitted?

I am the sponsor for their trip and they are going to live in my room which is a shared house. The room is very big so their accommodation should not be a issue.

I am eagerly waiting for some responses.

Thank you in advance.

Regards