'Require' refers to having a need or desire for something such as, "I require oxygen to live", or, "I require a pen to fill in this form". 'Request' refers to asking for something that you do not know if you will receive (you might not receive it/ you cannot demand it), such as,'Grant my last request, tell my wife I love her', or, "I request your company for dinner'.

"Require" means "need." For example, "Humans require food and water to stay alive." Without food and water, we will die. So, we require food and water. You could also say, "Humans need food and water to stay alive." "Request" means "ask for." For example, "I called the company to request the documents." I wanted the documents, so I called the company and requested, or asked for them. You could also say, "I called the company to ask for the documents."