If you look at Crow's Feet main page, there is a tab on the left labeled SUBMISSIONS. Under it you will find submission guidelines as well as this paragraph:

Become A Writer for Crow’s Feet If you’ve written a story that sheds light on the aging process, you may become a writer for Crow’s Feet and send us your piece for consideration.First, send an email to crowsfeet8@gmail.com with a link to the draft piece you’d like to submit or a link to other examples of your work. Be sure to include your @medium username. We require articles that are well-written and fully proofread. (If a piece doesn’t meet the guidelines below, it may be rejected.)If we like what we see, we will add you as a writer to Crow’s Feet.

I hope this was helpful. :) Have a great day & I look forward to reading your work.