splitting custom fields into 2 columns

You can try using an HTML table and use some PHP code in the columns – make sure to close PHP before and after the HTML. Change widths as you wish. I did inline CSS but you can also enqueue your CSS in a file if you prefer.

<table style="width: 100%;">
  <tr>
    	<td style="width: 50%;">
	
	Column 1

	</td>
    	<td style="width: 50%;">

	Column 2

	</td>
  </tr>
</table>

ok, but the code of all the custom fields is in the file functions, it’s a lot of stuff, how can I “order” to this html to work on the edit post page, right down the description default area of each post? thank you

Sorry. I misunderstood. What you are asking then is how to split the metabox that has the custom fields into multiple columns. I am not exactly sure how to do that as I have not done this myself. Without more details, such as exactly how it’s coded now, it would be difficult to know which approach to take to make this happen.