Hello.Please how long does my passport need to be valid for when applying for visa.My passport is expiring April can I apply for visa with it this January or I should renew?

Hello.Please if my sponsor is the owner of the company what are the documents I will submit and please can anybody help me with the link to the official website.I don’t think I am getting the right one because I can’t see any information apart from the visa form on the website I can see