Bulma is Goku's oldest friend since Goku first met her in the first episode of Dragon Ball. Unlike the other Dragonball characters, Bulma's major characteristic is not her strength, but her intelligence. She was able to construct a dragonball-radar, a shrinking device and a time-machine.
Bulma is one of the more hot-headed characters. She'll charge into any scenario purely for the thrill of it and is not afraid to tough-talk Vegeta, who is usually left speechless as a result. Bulma can also be extrememly shallow. She's well aware of the effect she has on men and has no problem with lusting after handsome men even while she's in a relationship or if they're bad guys.
Bulma is one of the more fashion-conscious characters in the series, frequently changing her hairstyle and outfit with every single appearance. She shares this trait with her ex-boyfriend Yamcha, Son Gohan and Android 18. She is also shown to be friends with Chi-Chi and Videl.
RomancesPilaf, Bulma and Yamcha quickly fell in love together. The relationship was not as romantic as either had planned it to be, as Yamcha's good looks got him noticed by other girls. Yamcha also started taking Bulma for granted early in their relationship, often leaving her to go train for extended periods of time. Later in Dragon Ball Z, Bulma and Yamcha broke up for good, though he still hangs out with her, implying that they're on good terms.
Trunks. The two still fight though and it's implied that they only got together because they were lonely.
After the defeat of Cell, Vegeta spends more time with his family, admitting that he had grown to love them. He also shows a more protective side as he yells at Goku for using Bulma as a bargaining chip.
In Battle of Gods, Beerus the Destroyer arrives on Earth and Vegeta is forced to put aside his arrogance and do everything he can to make sure Beerus doesn't feel tempted to blow up Earth. When Beerus lashes out at Bulma, Vegeta forgets how scared he was and unleashes his full wrath on him. Both scenarios show how Bulma's influence has ultimately made Vegeta a better man. After the final battle with Beerus, she returned her feelings back to Vegeta, showing that she loves him.
During DragonBall Super, Trunks comes back from the future and tells evryone about a new future threat, mentioning how this one killed the future version of Bulma. Vegeta then resolves to train so that he can exact his revenge.
In the future, she and Vegeta had a daughter named Bulla.
Goku meets Bulma mountain Paoz, when she was searching the Dragon Ball, Goku refused to give the ball four stars because it was the only memory she had left her grandfather, so Bulma tries to seduce just to give him the ball but still fails, Bulma then invites Goku to help him find the Dragon Balls, what he accepts and beginning their adventure together. Although at first he showed displeasure Bulma to Goku soon begin to have more confiaza you reaching become your best friend, along the various characters would seem to assume that Bulma has a romantic interest in Goku, although she denies it, Bulma has admitted that Goku is very handsome on several occasions; in the saga of Freezer she says she wishes that Goku was her boyfriend, but later dismisses it saying he had lost that opportunity. In the alternative future she mentions to Trunks that Goku always feel confident and made her feel everything would be fine. In one of the final episodes in the saga of Majin Boo, Chi-Chi believes that Bulma liked Goku.
Under Chapter 200 of the manga Dr. Slump, Akira Toriyama reveals a secret saying that (supposedly) Goku and Bulma to fall in love.