UK Immigration Visas

Misleading private business name.. Should at least add Ltd at the end or something so people don't think they are calling UK visa and immigration!!!

applied for a job in the United Kingdom, and I was accepted, and I was asked for documents and filling out immigration forms. I did, and after that they asked me for a certain amount to process the documents. The question is: What is the validity of that required amount, and how do I make sure that the party to which the
money was sent is governmental?
It is worth mentioning here that application sites such as Linkedin warn applicants not to pay any amount under any item