Create Link Manually
Go to your Tumblr dashboard and click “Customize” to open your theme settings page. Click inside the Description box in the left pane at the point where you want the link to appear in your sidebar. Enter the following line of code: Ask Me Anything Replace “Ask Me Anything” if you prefer to use another word or phrase for the link. Click “Save” and then “Exit.”
Create Link Automatically
Go to your Tumblr dashboard and click “Customize” to open your theme settings page. Scroll to the bottom of the left pane, and then click “Add a Page” to open a page creation window. Change the URL in the new window to “username.tumblr.com/ask”. Use your own Tumblr username instead of “username.” Enter a page title such as “Ask Me Anything.” What you enter here appears as a link on your sidebar. Enter anything in the description field – it doesn’t show up on your Ask page, but Tumblr won’t let you proceed until you enter something. Move the toggle switch at the top of the window to the right. This tells Tumblr to add the page title as a link in the sidebar. Click “Save,” and then exit the customization page. The link to your Ask page appears in the sidebar along with links to any other pages you create.
