The Airtable "Rich Text" column type is an excellent tool to update your product descriptions. As it allows you to format the content inside cells - introducing headings, bold text, italic text, etc. - this allows you to control the exact HTML of your product descriptions right from within Airtable. With a quick little configuration change AirPower will take your formatted text, convert it to HTML, and send it off to Shopify. Here is how.
First, change the type of the column you want to sync to your products' descriptions to "Long Text". Then enable the "Enable rich text formatting" toggle. You will immediately see visual shortcuts to format your text, but you can also use the tried and true Ctrl+B, Ctrl+I, etc. shortcuts.
Second, just run a Shopify-to-Airtable or Airtable-to-Shopify sync. AirPower detects that you have mapped the field to a rich text column, and will automatically handle things. In a Shopify-to-Airtable sync it will convert your description HTML to the rich text format, and during an Airtable-to-Shopify sync it will convert the rich text format to HTML as required by Shopify.
Happy editing!