custom form to post to custom field

You cannot just “post to a custom field”. You have to explicitly save each custom form field to the wordpress system, check: https://codex.www.ads-software.com/Function_Reference/update_post_meta

So far I have this on the form,

But im a litle lost when it comes to posting to custom fields.

<?php
if( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) &&  $_POST['action'] == "new_post") {

	// Do some minor form validation to make sure there is content
	if (isset ($_POST['title'])) {
		$title =  $_POST['title'];
	} else {
		echo 'Please enter a title';
	}
	if (isset ($_POST['description'])) {
		$description = $_POST['description'];
	} else {
		echo 'Please enter the content';
	}

	$tags = $_POST['post_tags'];

	// ADD THE FORM INPUT TO $new_post ARRAY
	$new_post = array(
	'post_title'	=>	$title,
	'post_content'	=>	$description,
	'post_category'	=>	array($_POST['cat']),  // Usable for custom taxonomies too
	'tags_input'	=>	array($tags),
	'post_status'	=>	'publish',           // Choose: publish, preview, future, draft, etc.
	'post_type'	=>	'log',
	);

	//SAVE THE POST
	$pid = wp_insert_post($new_post);

             //KEEPS OUR COMMA SEPARATED TAGS AS INDIVIDUAL
	wp_set_post_tags($pid, $_POST['post_tags']);

	//REDIRECT TO THE NEW POST ON SAVE
	$link = get_permalink( $pid );
	wp_redirect( $link );

	//ADD OUR CUSTOM FIELDS
	//add_post_meta($pid, 'rating', $winerating, true); 

} // END THE IF STATEMENT THAT STARTED THE WHOLE FORM

//POST THE POST YO
do_action('wp_insert_post', 'wp_insert_post');

?>

After this

//SAVE THE POST
	$pid = wp_insert_post($new_post);

You can save the custom fields in this manner:

//SAVE THE POST
$pid = wp_insert_post($new_post);

if($pid)
{
update_post_meta($pid, "fname", sanitize_text_field( $_POST['fname'] ) );
}

Ah ! I see, Thankyou.

You’re welcome.

Might of been a Little premature, as that didn’t work, i did find another way,

//SAVE THE POST
	$pid = wp_insert_post($new_post);

             //KEEPS OUR COMMA SEPARATED TAGS AS INDIVIDUAL
	wp_set_post_tags($pid, $_POST['post_tags']);

	//REDIRECT TO THE NEW POST ON SAVE
	$link = get_permalink( $pid );
	wp_redirect( $link );

	//ADD OUR CUSTOM FIELDS
	add_post_meta($pid, 'fname', $fname, true);

that didn’t work either.

Are you certain that the field names match with your system?
I just guessed and put names for you to understand. You have to make sure to change the field names.

Ive tried to keep is simple in advanced custom fields i created fname and in the form i create fname, so fname -> fname. But Ive now noticed my title field is blank on creation of new post

got the title back, made a error in name of input. NOW IT WORKS!

<!-- First Name -->
			<fieldset name="fname">
				<label for="fname">First Name:</label>
				<input type="text" id="fname" value="" tabindex="5" name="title" />
			</fieldset>

Great!