Microphone for outdoor wedding

We’re having our small ceremony and reception (100 guests) outdoors and I know it would be a smart decision to get a microphone so people can hear what’s happening. The problem is I have next to no clue about anything technological.
We decided not to go for a band or DJ because neither one of our families are big on dancing but we do have a friend providing a large Bluetooth speaker that’s great for the background music during both portions of our wedding. I just don’t know what kind of microphone I should be looking for.
Are they basically all the same? I’ve seen karaoke mics and ones that plug in but only to mic outlets vs aux outlets. It’s literally the last thing on our list of things to situate before the big day and it’s proving to be very stressful.