How do I attach a .blend file on my posts?

I see other users attach .blend files. I can’t figure out how.

I just wanna attach the .blend file of my infantry suit 3d model so someone can rig it.

go to www.pasteall.org copy the link and paste on your post.

You can use pasteall.org, but you should be able to attach .blend files the same way you would attach any other file to a post (scroll down and see the Manage Attachments button when making a new post from Advanced mode). There are size limitations regarding how large the file can be, but if you want to do it without leaving the site, that’s how.