That was very likely Street Complete which is self explanatory and a great way to start. You are adding all kinds of useful information about any kind of object or building with this.

There's also Vespucci which allows to alter the whole map (ie edit streets, POIs and so on) but takes a lot more to get familiar with.

Awesome thanks for the all this info!

Same here. If there’s a Handy tutorial anyone would suggest to get familiar with those abilities I’d love to hear about them.