Future generations certainly won't write on paper, and they probably won't need to learn how to write at all!

Electronic devices with (voice functions) will do everything for them."

Voice functions isn't wrong but not very detailed. You can also say speech-to-text/ audio transcription.

First of all, writing is an important tool to stimulate our brain, train our brain-muscle- memory and to help us form and understand our language on a deeper level.

the correct expression should be muscle-memory.

Furthermore, handwriting is crucial for communications, as soon as the Internet or the WiFi does not work anymore.especially when we lose Internet or WiFi.

The sentence could be more concise here.

Let's say, per example, th we lose power and all our networks went off, and now, i. If you wanted to contact someone, doing that via an electronic device or via (voice functions) will be nearly impossible.

This site explains when to use the adjectives electric/electronic/electrical: https://jakubmarian.com/difference-between-electronic-electric-and-electrical/
(): See my comment above.

I can agree with this statement to a certain point that electronic writing. -

misplaced period here I'm assuming. We can use a comma for emphasis or a dash (-) for a stronger emphasis.

may it be via computer or on our mobile phones, - is on its way to overtake the analog handwriting, since it can be faster, easier and isand easier to share.

See comment on dashes above.
No need to use "the" since we don't have a specific analog handwriting we're talking about (e.g. general statement: Cats are cute. Specific statement: The cat on top of the couch is cute).

Digital tools likefor grammar correction, spell check and translation programms also make digital writing more attractive, but I plead(/beg) you to never stop using analog handwriting as a tool, may it be for notekeeping, shopping lists or diary entries.

Optional: you can use "beg" if you want your voice to be more dramatic.

I can agree with this statement to a certain point that electronic writing.,

may it be via computer or on our mobile phones, is on its way to overtake the analog handwriting, since it can be faster, easier to do and is easier to share.