@Wannikea ********
I think that's pretty obvious. It's a one page summary confirming the individual is employed by x company since x date and a list of their duties. Confirmation the applicant works online or remotely. A brief summary of what the company does. Salary details may be included but don't have to be. Letter should be printed on company letterhead and signed and stamped by HR, company CEO/president or other authorized individual.
Should be addressed to consulate in question.