vendor/magento/module-sales/view/frontend/templates/email/items/order/default.phtml

<p class="product-name"><?= $block->escapeHtml($_item->getName()) ?></p>
<p class="sku"><?= /* @escapeNotVerified */  __('SKU') ?>: <?= $block->escapeHtml($block->getSku($_item)) ?></p>
<p class="color"><?= /* @escapeNotVerified */  __('Color') ?>: <?= $block->escapeHtml($block->getColor($_item)) ?></p>