Giving a speech or presentation online is similar to an in-person speech but there are a few things that make it different. Obviously not having an audience in the same room as you is the key difference, but not having the energy, and visual cues that the audience is following along is part of the missing audience element. In both situations, you need to research your topic, write your speech, and know your audience, but if you are presenting online you will also need to know the technical elements involved.
There are two general formats for online presentations; synchronous and asynchronous. Synchronous is when the audience is watching your presentation live as you give your speech, like a teams meeting. Asynchronous is when your speech has been recorded so that someone can watch it at a later time, think TicTock video. Many presentations end up as a blend of the two, the presentation is recorded live as you present so that some can watch at a later time, think Ted Talks.
Each of these methods has its own benefits and drawbacks and knowing them, and how to work with the method, is key to a good presentation. This page looks at some issues for online presentations you should consider when approaching each style.