To access the Oneflow platform you need be invited to your company-account by an Administrator. Upon invitation you will receive an e-mail which looks like this:

Click on the green button to complete your registration. 

Choose your password, approve the conditions and click on the blue button. Done!

Please note that the invitation link is active for 7 days. If you fail to confirm your registration within the time limit, ask your Administrator to resend the invite.

Note: 

For your security, Oneflow will not notify that you are trying to add a user that is already invited, it will simply not generate an e-mail to your inbox and you will think something went wrong, but it didn't. You always need to register through the invitation link sent from your Administrator.