The meeting ___ at noon. Please confirm your attendance.
Both versions of this message can work, and each tells your colleague something slightly different.
With will be: The meeting will be at noon. Please confirm your attendance. You are stating the schedule as a settled plan. Noon is the expected time, and you are simply asking them to confirm they can come.
With would be: The meeting would be at noon. Please confirm your attendance. You are presenting noon as the proposed or imagined arrangement, perhaps still open to change if people cannot make it. The message becomes a little softer, as if you are checking whether the plan works before treating it as fixed.
So will be reports a plan you expect to stand, while would be holds it lightly, as something that depends on the reply you get.
- The report will be ready on Friday. You are stating what you expect, no conditions attached.
Paired examples
will be points to a future state you expect. would be marks a condition, or a softer, imagined version of the same idea. The imagined version often depends on something else happening first, like The trip would be cheaper if we booked early, where the lower price only exists in that imagined situation.