Naruto would be angry. He's not the type to just accept being kidnapped. He'd immediately start looking for ways to escape. He might try to use his ninja skills to break free from whatever restraints Orochimaru has put on him.
Naruto getting kidnapped by Orochimaru would be a really dangerous situation. Orochimaru could start by putting Naruto in some sort of chakra - suppressing device. This would limit Naruto's ability to use his Nine - Tails power. Then, he might try to implant some of his cursed seals on Naruto, which would give him more control over Naruto. But Naruto has his own allies within himself. The Nine - Tails, despite their rocky relationship, might help Naruto out in this situation. Also, Naruto has the memories of all the people who care about him. He'd draw strength from those memories and keep his hope alive, waiting for the moment when he can break free and return to his friends and the village.
Well, Naruto could potentially be used as a bargaining chip by Orochimaru. Orochimaru might try to trade Naruto for something he wants from Konoha, like secret jutsu scrolls or some kind of political power within the village. And Naruto, being the determined hero he is, would likely be constantly looking for a way to escape and foil Orochimaru's plans.
Sakura would be worried sick. She might immediately inform Kakashi sensei and the rest of the village. Then, she would probably want to be part of the rescue mission. Sakura has grown stronger over time and would use her medical ninjutsu and combat skills to help save Naruto. She would also be constantly worried about Naruto's well - being and would encourage the others to move faster.
If Naruto was kidnapped by Orochimaru at birth, the entire Naruto universe would be drastically different. Konoha would lose its Jinchuriki, which could lead to a power imbalance. Without Naruto, the Nine - Tailed Fox's power couldn't be harnessed for the village's protection. Also, Orochimaru might have used Naruto's Uzumaki heritage and the power of the Nine - Tails for his own dark experiments. This could have led to the creation of more powerful and dangerous entities. His Akatsuki plans might also be affected as Naruto was a key part of their overall scheme.
Well, if Naruto is captured by Orochimaru in fanfiction, one possibility is that Orochimaru wants to use Naruto as a bargaining chip against Konoha. He may think that by having Naruto in his grasp, he can force the Hidden Leaf to meet his demands, like giving him access to certain forbidden jutsu or secret scrolls. Another aspect could be Orochimaru's curiosity about Naruto's ability to master new jutsu so quickly. He might want to study Naruto's mind and body to find out the secret behind his growth as a ninja.
She could use her shadow clones. Female Naruto might create a bunch of clones to distract Orochimaru and his minions while she makes her escape. Since she is known for her large chakra reserves, she can afford to create many clones at once.
If Naruto gets captured by Orochimaru in fanfiction, his friends' reactions would be intense. Hinata, who has deep feelings for Naruto, would be heartbroken but also very determined. She might try to secretly track Orochimaru on her own at first, using her Byakugan to search for Naruto. Kiba with Akamaru would be eager to jump into action, using their tracking skills. Lee would be excited to prove his strength and save Naruto, ready to use his Taijutsu skills against Orochimaru. His friends' combined efforts would be focused on rescuing Naruto from Orochimaru's clutches as soon as possible.
In fanfiction, if Naruto gets kidnapped by Akatsuki, he might be used as a bargaining chip. The Akatsuki could try to exchange him for something valuable like the Nine - Tailed Fox's chakra. Or they might try to extract the Nine - Tails from him forcefully. Naruto would surely put up a fight though, using his Rasengan and other jutsu.
Well, in most cases, his friends would likely try to rescue him. Sasuke might put aside his differences for a while and join forces with Sakura and the others. They'd probably start by gathering information about the council's motives and the location where Naruto is being held.