All about Wordpress Post

@ You know the category name want to know the category ID :

<?php
$cat_id=get_cat_ID("style");
echo $cat_id;
?>

@ You know the category name of category ID want to post Name, post ID,  featured image, post content: 

<?php
$posts_array = get_posts( $args );
?>

Here is the definition of the $arg:

<?php
$args = array(
    'numberposts'     => 5,
    'offset'          => 0,
    'category'        => ,
    'orderby'         => 'post_date',
    'order'           => 'DESC',
    'include'         => ,
    'exclude'         => ,
    'meta_key'        => ,
    'meta_value'      => ,
    'post_type'       => 'post',
    'post_mime_type'  => ,
    'post_parent'     => ,
    'post_status'     => 'publish',
    'suppress_filters' => true ); 
?>

I think it will be better to see an Example:

global $post;

<?php
$cat_id=get_cat_ID("style"); // get the category Id
echo $cat_id;    // print the category Id 
$args = array( 'numberposts' => 9,'order'=> 'ASC','category' => $cat_id );

$myposts = get_posts( $args );
foreach( $myposts as $post ) : setup_postdata($post);
echo $post->ID;   // print the Post ID
?>
<?php the_title(); ?>
<?php    
$feat_image = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );// get the Featured image
echo ""; // Print the image
endforeach; ?>