Answers for "get terms by id in wordpress"

get taxonomy term id from slug - WordPress

<?php 
    $term = get_term_by('slug', $slug, 'category'); 
    $name = $term->name; 
    $id = $term->term_id;
?>

wordpress get terms by taxonomy

You need to pass an additional argument to get_terms(). The default is to hide
"empty" terms-- terms which are assigned to no posts.

$terms = get_terms([
    'taxonomy' => $taxonomy,
    'hide_empty' => false,
]);