As others have mentioned, the question is a bit vague.
I have a Samsung Galaxy A20 smartphone and 2018 9.7" iPad. They work great together. Since Apple insists on keeping their ecosystem more closed than Google's, I lean to using Google apps and services. For photos, music, mail, etc. I can access and interact with my information equally easily from both my Android phone and iOS tablet.
For productivity on-the-go, I use Google Docs suite. This has allowed me to simply take my phone and pocket folding-keyboard to meetings rather than a laptop or iPad w/keyboard. Then when I'm at my office or home, I can pull up my notes and then rework them into something for long-term use.
But for documents that I need to print and/or distribute, I use iWork (specifically Pages and Keynote). I can work on these docs seamlessly on my iPad, iMac, Macbook Air, or Google Pixelbook. I haven't tried using iWork on my phone yet (that's next on my list). Also on my list is the screen projection capabilities... it sounds like I should be able to cast my phone's screen to a TV... couple that with support for keyboards and mice, and there is some promising possibilities... Once I have time to experiment with these, I'll start a thread in here describing what is possible.
At this point in time, given the current state of iPhones and the direction that Apple is going with them, I can't see myself going back to an iPhone.
The combination of the Apple Pencil 1 + 2018 iPad + my Digital Planner/Journal for GoodNotes, has completely eliminated pen and paper notebooks. As much as I enjoy my Pixelbook and Pen, the state of the quality and quantity of Pen-supported apps for Chrome and Android is abysmal... worse than the early days of the Surface RT (and THAT was bad!).