How to transfer information from TRELLO to a computer and will it be usable?

[1-Чижик С. И.]

We are contacting you to let you know that Atlassian is winding down its operations in Russia and Belarus, and our records identify you are using Atlassian's no‑charge product(s) within these identified regions. As such, this email constitutes notice that, in accordance with our Cloud Terms of Service, we will terminate your Atlassian account in 30 days.

[Sal]

Hey @1-Чижик С. И.! When exporting your data from Trello, we'll allow you to export all your boards in a JSON format (or CSV if you have Premium), allowing you to reuse it elsewhere. But, we can't guarantee your exported data will work on other services. 

You can read more about exporting your data from Trello here: https://support.atlassian.com/trello/docs/exporting-data-from-trello/ 

[1-Чижик С. И.]

I won't be able to use Trello. Trello leaves Russia.
I need to save the information in text form suitable for future use.
Is there a way to save at least cards, descriptions and attachments, even without checklists?

[Sal]

As I mentioned @1-Чижик С. И., you can export your data on Trello either on JSON or CSV (Premium only), but you can't export it on text only. Also, yes, you can export your cards with everything regardless if they do or don't have a checklist. I hope that helps!