Audio Mixer and iPhone setup for podcast/YouTube videos?

I'm looking at starting a podcast/YouTube channel. I will be conducting interviews so will need 2 mics minimum. I'm going to be using just my phone for now to record the video however I'm a bit stuck on the audio. Can I hook up my iPhone to an audio mixer and then hook the mics into the mixer to record audio and video that way? If so, do I need some sort of adapter to go from the mixer to my phone? I'm new to all this and just want to make sure I'm doing it correctly!

Forget the phone.

Start by getting a basic but decent camcorder, which will cost between $180 and $300.

For sound, use a portable digital audio recorder such as the Tascam DR-05.
It costs only about $100 and will serve many needs, both simple and sophisticated.

Use a video editing program to combine and sync the video with the audio.

You really need an audio interface rather than a mixer. Feeding to the phone (or any other device) as analog audio is going to give extremely limited quality.

You can get good interfaces with extremely high quality that can be recognised by an iphone as well as a pc/laptop.
eg. A focusrite Scarlett 2i2 or 2i4 can work with an iphone or ipad.

Once you have a decent audio interface you can connect any mics you like, from cheap electret ones like NW700 all the way through true studio-grade ones.

It's also pretty much future-proof, eg. If you move on to PC based editing or a mobile laptop-based recording setup, it will be equally useful.