Does this mean toilet paper is banned?
Paper towels are banned?
Food wrappers made wholly or partially of paper are banned?
Is cardboard packaging banned? Does cardboard count as paper?
Are paper sticker labels for shipping banned?
Are paper/sticker labels on all kinds of products not packaged in cardboard banned?
... I am curious as to your answer, but I struggle to concieve of a society where everything is done on electronic devices, but somehow also all kinds of paper and paper based products common to many households and vital to the supply chain and logistics that produces and distirbutes the electronic products are also banned, entirely.
Even if the answer is somehow yes, all kinds of paper based products are banned and replaced with metal or plastic or glass or something...
Clay tablets. Whittle a stick into something that can make impressions on it, bake the tablet, or really any kind of pottery.
Use a knife to etch writing into pieces of thin plastic, or wood.
Use a laser engraver to engrave glass or metal.
Make crude ink or liquids capable of staining on your own from raw ingredients, write on thin fabrics, white fabrics like cheap t shirts or certain kinds of gauze or bandaging, again with a whittled stick, a chopstick, a feather, etc.
You didn't say paint is banned. Spray paint stuff. Make stencils out of thin plastic or metal.
Glue toothpicks to thin plastic.
For any of these methods, you can make up your own language or pictogram / hobo sign style system of symbols to convey whole concepts.
And for most of these methods, the object with the writing or the writing itself on it can be destoryed by fire, immersion in water or pulverization, for more resilient material use a dremel or radial sander/grinder to obliterate the message.
And this is all just homebrew ways to do writing.
Tons of other ways of communicating.