To add to the other comments- follar and joder are valid in Spain, however in South America “joder” means to joke around, whereas “coger” is used as a direct translation of fuck.
In Spain though, “coger” means to grab, and as you can imagine the different use for the same words makes people giggle in a variety of situations (such as when consuming foreign media )
Is there a direct translation for the word “fuck” in Spanish? 
Follar
Adding to the other comment, “joder”. Closer to fuck as a curse word.
What the two other guys said, but clarifications are needed.
However, there are execptions, as you can say both “que te jodan” or “que te follen” to say “fuck you” to someone in Spain.
Bonus way to say “fuck you”: Que te den por culo = Get fucked in the ass
Why am I having so much fun explaning these?
To add to the other comments- follar and joder are valid in Spain, however in South America “joder” means to joke around, whereas “coger” is used as a direct translation of fuck.
In Spain though, “coger” means to grab, and as you can imagine the different use for the same words makes people giggle in a variety of situations (such as when consuming foreign media )