I would like to direct your attention to an email support ticket that the team sent with Ticket #31224315. Kindly check your email inbox for more information about your account. Please don't hesitate to update the same ticket thread regarding your account so that you can be assisted further.
As for your question, feel free to upload screen grabs or a PDF file of your blog articles. Your portfolio is where you have the opportunity to impress potential clients with real-life examples of your skills and expertise. Use your portfolio to show off projects related to any or all of your skills, so long as you personally have worked on every item you add and adhere to all of Upwork’s Terms of Service. Like the rest of your profile, posting contact info isn’t allowed in your portfolio. That means these files (and linked sites) can’t include your email address, phone number, or chat ID. You may read more about adding a portfolio here.