tumblr homepage, click on "submit."
Read the rules of submission. This is very important! Your submission will not get published if it does not follow the rules of submission.
Once you've read the rules, you'll see a box that says "Submit a Text Post." If you click on the writing, a drop-down menu will appear, like in the photo above. Select what type of submission you want to make (in this example, I will show you a photo post).
Click on "Browse" and your photo files will come up. Click on the photo you want to submit. In the text box, type in whatever information you want to include. For example, you can tell us where you got your outfit, where you wore it, etc. Don't forget to include your size!
Next, you'll need to check the box that says "I accept the Terms of Submission."
If you want to add tags to your submission, you can select them from the list provided.
When you are satisfied with your submission, click "Submit."
If you see this come up on your screen, your submission has been entered!
If you don't see this, start over and try again. Tumblr may be having the hiccups.
Again, this particular example was for a photo submission, but it will essentially be the same for text/link/quote submissions as well.