I use the Florida Trail app when hiking the Florida Trail. It's been very helpful with planning, etc. More than once it found the trail for me when I couldn't see a trail or a blaze.

I've used various tracking apps over the years. My current go-to app is Map My Hike. It maps the hike, elevation, pace, etc. It's nice for training hikes.

While I almost always have my phone with me, sometimes I hike just to hike and don't use an app at all.