How to inject alt and title attributes for every image in each post into HTML?

Question

My sincere apologies if the following is completely way off as I'm new to this.

This previous answer looks like what I'm trying to find, but I'm not sure what to do with this information.

From what I can tell, I need to be working with wp_get_attachment_image to inject the alt and title text for every image in every post.

My theme is loading in post content with the_content();, and after looking at the Wordpress Developer page for the_content(); I'm guessing that this function is calling post-template.php.

The only section I can find in post-template.php that contains wp_get_attachment_image is as follows:

if ( $text ) {
    $link_text = $text;
} elseif ( $size && 'none' != $size ) {
    $link_text = wp_get_attachment_image( $_post->ID, $size, $icon, $attr );
} else {
    $link_text = '';
}

After looking over this answer, I'm guessing I need to do something like this with the above code:

if ( $text ) {
    $link_text = $text;
} elseif ( $size && 'none' != $size ) {
    $image_alt = get_post_meta( $image->id, '_wp_attachment_image_alt', true);
    $link_text = wp_get_attachment_image( $_post->ID, $size, $icon, $image_alt );
} else {
    $link_text = '';
}

I've passed the variable $image_alt in place of $attr here.

Again, I imagine this is very wrong, and my apologies.