wordpress page.php styling and markup

I have a couple of questions related to building a custom theme with Wordpress.

1) If the website is made up of pages, I can use page .php to run the LOOP and retrieve content. In this case, is it OK to paste the content (of each page) using the backend of word press - I.e. paste all content and HTML markup into the 'text; . Is this a reliable way to enter content and accompanying markup into the database?

I guess the advantage is that users will then be able to edit the content themselves using the visual Tab.

Many thanks, P