The moment you push your changes to origin, other developers can then pull them. If you intend to squash or fixup commits, then you should do so after committing to your local git, but before you push to origin.
Once you push to origin, the commit hashes from your local branch become what origin has, and then those commit hashes are now possibly on another developer computer after they pull.
If you do a squash or a fixup, the existing commits are effectively rewritten into a new commit with a new hash so the developers who happened to pull what you previously pushed now have their HEAD pointing to a hash that no longer exists — thus orphaning.
The moment you push your changes to origin, other developers can then pull them. If you intend to squash or fixup commits, then you should do so after committing to your local git, but before you push to origin.
Once you push to origin, the commit hashes from your local branch become what origin has, and then those commit hashes are now possibly on another developer computer after they pull.
If you do a squash or a fixup, the existing commits are effectively rewritten into a new commit with a new hash so the developers who happened to pull what you previously pushed now have their HEAD pointing to a hash that no longer exists — thus orphaning.