Within the world of business, one is often called to attend numerous meetings. There's staff meetings, project meetings, governance meetings and more. Many will be called by someone else and you'll simply be an attendee. Regardless of your role within an organization, a one-on-one is entirely different as it's owned and driven by you, the employee, to your manager.
Many fall into the fallacy that because your manager is your superior, or because they might have things that they want to talk to you about, that they own the meeting. The opposite is actually true, regardless of what any manager may let on. A 1:1 is a meeting owned and driven completely by the employee. If your manager has other topics that aren't covered or if there isn't enough time for them in your 1:1, then they can call their own meeting to cover these items.
This unusual direction of ownership is intentional. The idea is that there are going to be topics, such as career direction, that might only be brought up from the employee side of things. As such, it should be made clear that the meeting and the time allotment is solely theirs. Additionally, there are topics that a manager may not have any inkling about, such as an employee seeking guidance to a sticky situation that they're having or a problem they're trying to solve.
But this is not to say that a 1:1 is fully rigid. The manager can suggest and recommend topics to be included in the one-on-one agenda. If agreed to by both parties, then one can kill two birds with one stone and potentially eliminate a different meeting to be held in the future. But sometimes another meeting is unavoidable due to lack of time in a 1:1 or other more immediate topics at hand.
When starting off on your journey with 1:1s, remember who has ownership of the meeting, it's the employee not the manager. By setting clear expectations up front, you can eliminate much back and forth with a manager in the scheduling, running of the meeting and related meeting activities such as minutes.