The elements that appear on your Tumblr site, from tags to author names, are set by the theme you're currently using. If you've applied a theme that displays author IDs next to posts, you can hide them by editing the theme HTML directly and removing all of the author placeholders. Editing the HTML of a theme breaks the auto-update feature in order to protect your modifications, so you'll have to manually install any future versions of the theme released by the author if you want to apply them.

Step 1

Log in to Tumblr, select the blog that you wish to work with from the top of the Dashboard, and then click “Customize Appearance.”

Step 2

Choose "Edit HTML" below the theme thumbnail to change the code of your theme.

Step 3

Look for references to "{PostAuthorName}", "{PostAuthorTitle}" and "{PostAuthorURL}", and then remove them from the code. If there are any references to "{PostAuthorPortraitURL-xxx}", then remove these too.

Step 4

Click "Update Preview," and then select "Save" to confirm your changes. Use the back button and the "Exit" button to return to the dashboard.