Super easy - Just replace the post ID 123:
$value = get_field( "text_field", 123 );
What about repeater fields?
I'm glad you asked. Here's a PHP snippet to echo the values for a repeating field that I've called logo (just remember to change the ID 1862 to match the post or page ID):
while( have_rows('repeater', 1862) ): the_row(); the_sub_field('logo'); endwhile;