Yamaha MG10. $199.

1/4" and XLR 3-pin ins and outs.. EQ (bass/treble control) on channels. Has a few extra channels more than you need at this moment, because you WILL eventually need "1 more channel"... You could go smaller/cheaper on the mixer, but you'll likely outgrow it quickly. Stay with Yamaha, Mackie. Don't get 'Harbinger' (from Guitar Center), I'd stay away from Behringer's cheap stuff as well.

https://www.amazon.com/Yamaha-MG10-10-Input-Stereo-Mixer/dp/B00I2J4TWG

If anyone will be singing in the mic, now or in the future, the FX model with reverb is only $30 more.

https://www.amazon.com/Yamaha-MG10-10-Input-Stereo-Mixer/dp/B00IBIVL42?

You'll need a Lightning to 1/8" TRS female adapter, and a 1/8" TRS male to dual 1/4 TS male cable. 1/4" ends go into channels 3/4 L+R. Cables to house speakers come from "Stereo Out" in blue box on mixer. Done.

https://www.amazon.com/Apple-Lightning-Headphone-Jack-Adapter/dp/B01LXJFMGF

https://www.amazon.com/Cable-Matters-3-5mm-6-35mm-Breakout/dp/B07PHVMTNT

Yamaha makes excellent mixers. If you can afford it, I highly recommend the 10 channel version of that mixer as it has vocal compression. Vocal compression makes it so you can hear people who sing quietly and people who scream into the mic almost equally loud. It's awesome for karaoke.

Additionally your speakers will need to be active (powered) unless you also buy an amplifier.

Behringer makes very good affordable powered PA speakers. Yamaha also makes good ones, but they are more expensive.