I am *not* a great thumb typer, so I don’t tend to do a lot of typing on my iPhone when it comes to using mobile offerings in Microsoft 365. However, the ability to dictate Outlook emails on my iPhone and iPad makes it much more likely that I’ll send emails while I’m away from my laptop. Here’s how it works…
Here I have my Outlook Inbox on my iPhone mobile app. To send an email, I click on the Plus icon in the lower-right corner:

When the new message screen appears, I place my icon into the body area of the email and then click the Microphone icon:

I can start talking, and my voice is translated into text. I can also use commands like “period” if I want to get a period at the end of a sentence (or I can click the period icon):

Once I’m done with the text of my email, I simply need to add a recipient in the To field and then click the Send icon in the upper-right corner. Given my lack of skill with thumb typing, this saves me a lot of time and frustration.