Hernandez is one of a number of new arrivals at the London Stadium as Slaven Bilic looks to build a squad capable of improving on the 11th-placed finish last season.
Manchester City goalkeeper Joe Hart has joined on a season-long loan while his former team-mate at the Etihad Stadium, Pablo Zabaleta, has also come in.
The club broke their transfer record to bring in Stoke's Marko Arnautovic with midfielder Sead Haksabanovic signing from Halmstad earlier this week.
Hernandez is a big fan of Hart and believes the new crop can help West Ham qualify for continental competition.
“The European spots are the main goal for us this season. No doubt,” he said. “Joe Hart is a great lad, a great professional. He always gives 100 per cent on the training ground.
“He has been in the national team for so long, playing in the Champions League, he is a great goalkeeper."