Venom may swear in the comic books, but it's not a constant thing. Sometimes it's used to add an edge to his character or to make a scene more intense. Different writers handle this aspect differently depending on the tone they want to set for the story.
The initial Venom comic was 'The Amazing Spider-Man #298'. It marked the beginning of this popular character's comic book journey. Since then, Venom has become a fan favorite.
The 2018 Venom comic is pretty good. It has interesting character developments and some cool action scenes. However, it might not be for everyone. You should give it a read and decide for yourself.
Venom belongs to the Marvel Universe. DC has its own roster of characters, but Venom isn't among them. Marvel has developed the Venom storyline and character over time.