Hi, ​@Arman Shayan!

There's no such option in Manychat. 

But you can achieve it using something like this:

1. Create and clean a Custom Text Field.
2. Use the Data Collection block (Multiple Choice) to set your option up.
   - This block makes it easier to do follow-ups and populate your field

   

3. An Action step populating your Custom Field this way:

   

4. A message informing the selections made and asking if the contact wishes to add another entry.
   - If YES = Goes back to the selection
   - If NO = Continues the flow

Test it. It's fun!

Hope it helps

And in the text_field, only the last choice will be saved, right? And for second and third teams need another fields?

No, just that.

The logic behind is that it will always get the current value of the field and add the last text input (in this case the option) below.

For the first time, the field will be empty and only show the option selected. Every time the user goes back and select another one, it will be inserted bellow.