Let's deal with a small and powerful tool for editing texts on your Blog form page.It's called "CKEditor", here we are going to use version 5.

First create a page for editing your blog, then add this little code.

[*blog_form]bid=blog,ud=edit-0.html||
%notify%
Title:<br/>%title%<br/>
Text:<br/><textarea name="text" id="editor" ></textarea><br/>
Category:<br/>Others<br/>
%submit%
[/blog_form]

Then add this code on the "footer" page and that's it, see the result below.

<script src="https://cdn.ckeditor.com/ckeditor5/34.2.0/classic/ckeditor.js">
</script> <script> ClassicEditor .create( document.querySelector( '#editor' ) ) .catch( error => { console.error( error ); } );</script>

Result