Yes, you can access the Canva button on Social's publishing window to make changes to your designs before publishing.
Access the Canva button from the media attachment icon on the publisher.
These are the steps to follow:
Step 1: From Zoho Social's dashboard, go to New Post.
Step 2: Click on the Media attachment button on the menu tray on the bottom right
Step 3: Select Design on the Canva button
Step 4: This shows the shortcut templates to choose from
Step 5: Choose from the listed social channel templates for Facebook/Twitter/Instagram or the general template with the "Social Media Post" button
Step 6: The Canva Frame opens with the selected template, edit an image, or design a new one from scratch
Step 7: Once you are done, click Attach to add the image to Zoho Social