A tagline is the single line that says what a product is and who it is for. It sits under the name on a landing page, a launch platform and a directory listing.
A good tagline names the thing in plain words, such as "invoicing for freelancers", so a stranger scrolling a list knows at once whether it is for them. Clever lines that need explaining lose that reader.
It is also what search engines and AI assistants read first to decide what your product is, so the plain name of the category belongs in it.
Why it matters for a launch
On a launch feed your tagline is nearly all anyone sees. It decides whether they click, more than the logo or the name.
Read more: How to write a product tagline