I can not upgrade my plan

Few days ago I signed up for a new basic account and my school has bought a pro license. I have the activation key but neither at the website or the App I have the option to enter my activation code. I have already watched videos of how to do it but the button does not appear on my screen. How can I do it?

Thanks in advance.

Fixed! I could do it on a laptop. I was trying to do it on an android smartphone and on an iPad.

Apologies for the delay in getting back to you but we’re glad to hear the issue has been resolved. Please let us know if we can do anything else to help. Thanks