My washing machine drainage hose is too short. What can I do?

The washing machine is a Samsung WF8602NFW. The sink has a spigot for the hose, but the hose is too short. I live in a block of flats so I have to make sure that I do not get any leaks. I am not sure what I should be buying to extend the hose. The hose is 21mm size diameter, which I think is pretty standard. Also should I use an inline anti-siphon device as well? Whereabouts would that be placed? Near the spigot? Or somewhere further along? I have searched on the internet and can't find any help, yet it must be a common problem. Thanks, Louise