They might get married and start a family right away. In fanfiction, it's common to see them settling down and having kids, living a peaceful life after all the chaos of the battle.
One possible scenario could be that after the intense battle, Harry and Ginny find a quiet corner in the ruins. They look at each other, all the emotions of the battle still fresh in their eyes. Ginny reaches out and touches Harry's face gently, and then they slowly lean in for a kiss, a kiss full of relief that they are both alive and still have each other.
In some fanfictions, Harry and Ginny might fight side by side, using their respective magical skills. Ginny could be shown as a fierce fighter, using her Bat - Bogey Hex to great effect against the enemies, while Harry uses his Patronus to protect them from Dementors if any are present during the battle.
One possible scenario could be that they have a peaceful family life. They might raise their children in the wizarding world, teaching them about magic and the values of love and courage. Harry could be involved in the Ministry of Magic, perhaps working on improving the safety and equality in the wizarding community. Ginny, on the other hand, might continue her career as a Quidditch player or become a Quidditch coach, passing on her skills and passion for the sport.
In some fanfictions, they might go on adventures together. Exploring the wizarding world more fully, perhaps seeking out new magical creatures or ancient magic. They have a thirst for discovery after the chaos of the war. Harry's knowledge and Ginny's courage would make them a great team on these excursions.
Maybe they go to a wizarding cottage in the countryside. They explore the nearby magical forests together, discover new magical creatures, and Ginny could teach Harry some new Quidditch tricks in the large open fields around the cottage. And of course, they have cozy evenings inside, cooking together and snuggling up by the fireplace.
One possible scenario could be that they meet in the ruins of Hogwarts. The war has just ended, and there's a sense of relief and newfound hope. Harry spots Ginny among the crowd of survivors. Their eyes meet, and without a word, they rush into each other's arms and share a passionate kiss. It's a moment of pure emotion, a celebration of their survival and their love that endured through the dark times of the war.
One possible scenario could be them renovating their home at the Burrow. They might be adding new rooms for their future family. Ginny could be using her magic to make the place more cozy while Harry helps with the physical labor, like moving furniture with a levitation charm.
In some fanfictions, it might occur during a trip on the Hogwarts Express. They are sitting in a compartment, just the two of them. The train is chugging along, and the scenery outside is passing by. Harry looks at Ginny and starts a conversation about their future. Then he casually asks if she would like to go on a date with him when they get back to Hogwarts. It could also be after Ginny has been in some sort of danger. Harry is so relieved when she's okay that he blurts out his feelings and asks her out.
Another possibility is that they would take a stroll in the moonlight around their new home. They would hold hands and reminisce about their adventures at Hogwarts. Harry might tell Ginny how much he loves her all over again, and Ginny would respond with sweet kisses, and then they would go back inside to have a warm drink and cuddle by the fireplace.
In fanfiction, they might start to rebuild their lives together. They could focus on their relationship more deeply, perhaps getting married and starting a family soon. Harry could finally have the peaceful life he always desired with Ginny by his side.