Create collection of data for a specific data

Example: When I press on to do list, it opens itself. Inside this to do list, when I press on To do button I want to make new record of what to do. I want to make a list of them. How?

Bind your input field to a page variable ‘to do list 1’ that is a list of objects with a property ‘input text’ for example.
To create a list of record in that to do list 1, you need to use the WITH_ITEM() formula in the assigned value field of your page var, like that:
WITH_ITEM(your_existing_list, {text_record_to_add_to_existing_list}

Thanks a lot, I will try to implement this.

Note that this page variable acts as a bucket or placeholder. It is there to just add your new text record to an existing list already created in your database. This mean you need to attach a createRecord flow function after this pageVar in order to actually save that newly updated list into your DB.