PHP how to edit a post with selfmade admin page database sql

I have a database blog with php, with a form where i can fill in the text, when i click submit it posts the text on my blog. I already know how to delete the post, but now i would like to know how i can edit it. This is my code to delete it if(isset($_GET['page'])) { if(is_numeric($_GET['page'])) { $deletePost = mysqli_query($conn, "DELETE FROM post WHERE postID ='".$_GET['page']."'"); echo 'post is verwijderd!'; echo '<meta http-equiv="refresh" content="0.1 adminPage.php">'; } }