There are a lot of quests to complete in Genshin Impact, including special characters quests for the various NPCs and characters that you will meet while playing the game. Lisa, your friendly lightning throwing librarian, has a quest called Troublesome Work.
During this quest, Lisa will ask you to help her get back a book that has not been returned to the library. As you go about completing the quest you will end up visiting lots of stores and vendors with Lisa, and you can buy her a small gift at each one.
When you visit Marjorie, the owner of the With Wind Comes Glory shop, you should get her the Ragged Old Scroll. As a librarian, Lisa will really appreciate this present. When you visit the Good Hunters food stall, you should buy her a Raddish Veggie Soup. Lisa is a vegetarian so won’t enjoy the meat options at all, and the other salad options are not quite fresh, so this is the best option.
Finally, when you visit Donna, the flower seller, you should get her a Cecilia. She will really like this flower. Once that is all done it is time to finish the quest, so simply use your Elemental Vision to find a trail at the main entrance to the town and follow it.
It does not seem that the gifts you get actually matter, at least not in any way that we have been able to work out yet. It’s still a good idea to try and get her the best possible presents, just in case it matters further into the game.