This is just a brief outline based on my own experiences. Feel free to add in any advice, tools, or suggestions. And, just in case you don’t know what a podfic is, it’s an audiobook version of fanfiction.
1. I want to record but I don’t have recording equipment
You can record an audio file on your phone or use free audio recording software Audacity. I’ve used both, but these days I prefer audacity because I find it easier to remove my flubs and rerecord without having to start at the start.
2. Where can I host my files? AO3 doesn’t do hosting
I got myself a free soundcloud account. There are other audio hosting services out there. Find the one you like the best.
3. How do I post it so people can find it on AO3?
Once you have the file hosted on, for example, soundcloud you can click on “share” and then “embed”. Copy the embed code and paste it into your fic on AO3. Make sure you’re in html editing mode at the time.
If you have the mp3 file hosted elsewhere (I’ve recorded mp3s on my phone and hosted them on google drive, for instance), you can use the native audio player available in AO3. Here’s how.
4. How do I tag it?
Add the tag #podfic to your fic. You can post the podfic on its own, or you can post it together with the fic text. I just started a new story last night and I’m going to podfic each chapter as I post and embed the player at the top of the chapter.
There are more specific tags as well that mention how long the podfic is. If you enter “podfic” into the additional tags section on AO3, the others will pop up.
5. I don’t want to record it myself, but I’m happy if someone else wants to
Use the tag #podfic welcome. This will allow people who record podfic to know that you’re open to it. You can also add a statement to your AO3 profile that lets podficcers know that they have your permission to record. You can see an example of this on my profile. This is not the only way to do this, but it gives you an idea of the type of things you can say.