Are upload request recipients limited to users of EasiShare?

No. Upload request recipients can be anyone outside your organisation.

After you have made the "Upload Request", the recipient will receive an email containing an EasiShare upload portal link. 

Note: You can secure the link by turning on the SMS OTP (one-time PIN). When the recipient tries to access the link, the recipient must key in the OTP token received on the phone to ensure the recipient is an authorised user.