Edit the contents of a post you added to your Tumblr blog by selecting the post and clicking Edit. Alternatively, edit existing tags or add new ones to several posts at once by using Tumblr's Mass Post Editor.
Edit the Contents of a Post
Step 1

View your blog's posts by opening the Account menu in your Tumblr Dashboard and clicking Posts under your blog's name.
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Step 2

Hover your mouse cursor near the top-right corner of the post you want to edit and click the dog-ear to reveal a page containing the post.
Step 3

Click the Edit button.
Step 4

Edit your post's title, body or tags and click the Save button.
Edit the Tags of Several Posts
Step 1
Open the Account menu and select Posts under the applicable blog.
Step 2

Click the Mass Post Editor link in the sidebar.
Step 3

Select the posts whose tags you wish to edit by clicking them.
Step 4

Edit the selected posts by clicking:
- Delete to permanently delete the posts from your blog
- Edit Tags to modify the posts' existing tags.
- Add Tags to insert additional tags into the posts.