What a TikTok caption is for
The caption is the text under your video. TikTok reads it, along with the words spoken and shown in the video, to decide who the video is about and who to show it to. Viewers read it while the video loops. So a caption has two readers: the system that sorts videos by topic, and a person deciding whether to comment.
That is why a caption that names the subject plainly ("repainting a thrifted dresser sage green") does more than a vague one ("obsessed"). The plain one tells TikTok what the video is. Then one line that invites a reply gives the viewer something to do.
Short caption or long description?
TikTok allows long captions, and long descriptions have become their own format: a short story or a list of steps that people stay on the video to finish reading. While they read, the video keeps playing, and that watch time counts.
Use a short caption when the video explains itself. Use a long description when there is a story behind it, steps to follow, or details people will ask for in the comments anyway. The generator writes either: choose Long for five descriptions of 300 to 500 characters with line breaks.
Hashtags that help
Three to five hashtags that describe the video are enough. Broad tags such as #fyp tell TikTok nothing about your topic. A tag that names what is in the video (#thriftflip, #dressermakeover) puts it next to videos that the same people already watch.
The captions written for you come with their own specific hashtags. In the ready-made library, add your own, since the captions there are written for any topic.