Thank you for your answer Long.
I tried inserting it into the view like this:
{% set files = mb.rwmb_meta( 'dodaj-dokumenty', user ) %}
{% for file in files %}
{{ mb.get_the_date( 'd.m.Y' ) }}
{% endfor %}
but I can't get it work.
I get an error whenever I try to modify the code and get the variables.
And if I just insert it like this:
{% for item in field %}
{{ mb.get_the_date( 'd.m.Y' ) }}
{% endfor %}
I obviously get the page publish date.
I would appreciate if you could help me further on this and get the code right.