Now we can use 1C training version but it is very uncomfortable because it limit too few quantity of documents. If I want to raise quantity of documents, how can I do it?

Hello, Ninh Giang Thi!
There are two possibilities:
1) You can buy a commercial version. At a time we have Not For Resale version for partners. For more details write an email to
int@1c.com
2) If you would like to continue using the training version and need some (let's say tiny) additional capabilities you can suggest it here and we will think about it.

Starting from version 8.2.17 the limitations of training version were relaxed. Hope you'll find this useful.