Using Dayfolio on two reMarkable devices
Same account, same planner
Your planner is a document in your reMarkable Cloud account. Every tablet signed in to that account downloads it, so a second reMarkable needs no setup in Dayfolio at all: open the planner on it and your handwriting is there too, kept in sync by reMarkable. There's no per-device charge.
Two full-size tablets (a Paper Pro at the office, a reMarkable 2 at home, say) share the planner as it is. A Paper Pro and a Move have different screen shapes, so there are two ways to combine them.
Option A — one shared file (same handwriting on both)
Keep a single planner and open it on both tablets. Handwriting is one set of notes, wherever you wrote them. On the tablet whose screen doesn't match the layout, use ⋮ menu (three dots) → Adjust view → Fit to height — see Planner looks narrow, small or cut off.
Which layout to choose for the shared file:
Move layout on both — full-width on the Move; on the Paper Pro, Fit to height shows it tall and centered. This is what most people who carry both pick, since the Move is usually the tablet that's in hand.
Full-size layout on both — natural on the Paper Pro; on the Move, landscape orientation gives the page more width.
Option B — one planner per layout (two files)
From your planner page, Keep both planners creates a second planner in the other layout with the Additional Planner license. Both planners sync on their own schedule; calendars and tasks are set up on each (they're per planner — see Combining calendars from several accounts). Each file has its own handwriting: notes written on the Move planner aren't on the Paper Pro planner, and vice versa. See Handwriting stays in its planner file.
Choose A when your notes matter more than the fit; choose B when each tablet should look its best and you write on one of them mostly.
Two people, two accounts
For two people with two reMarkable accounts (an executive and an assistant, for example), each person needs their own Dayfolio subscription, with a planner in their own account connected to the same shared calendar — see Combining calendars from several accounts.