How can PHP developers effectively utilize the Flex model or Grid system in Bootstrap for layout design?

To effectively utilize the Flex model or Grid system in Bootstrap for layout design, PHP developers can use the predefined classes provided by Bootstrap to create responsive and structured layouts. By applying these classes to HTML elements generated by PHP code, developers can easily control the positioning and sizing of elements on the page.

<div class="container">
    <div class="row">
        <div class="col-md-6">
            <p>This is a column that takes up half of the container width on medium screens.</p>
        </div>
        <div class="col-md-6">
            <p>This is another column that takes up the other half of the container width on medium screens.</p>
        </div>
    </div>
</div>