You can format the source data in Google Spreadsheet in different colors, fonts and sizes and all your cell formatting will be retained in the email messages.
Very handy code snippet from Amit Agarwal which lets you convert the formatted text in a Google Sheets cell to HTML. In the example Amit uses the formatted text in an email sent with MailApp
but you might find other uses for this solution. Click through to the source link for all the details…
Source: How to Preserve Formatting of Spreadsheet Cells in Mail Merge – Digital Inspiration
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.