Cloud storage (ie, Dropbox and similar)
It can be useful to to share files between multiple systems, such as your desktop, laptop and perhaps mobile devices. The best-known example of this is Dropbox, but Dropbox is not the best choice for work-related materials, for one principal reason: data protection. Dropbox is located in the US, and you therefore must not store any 'personal data' on it.
Instead, the University provides OneDrive that can be used for storing your data and Microsoft Teams for content that is intended to be shared with other staff.
Other cloud services §
You are free in general to use other cloud services of various types. Do bear in mind, however, that the Data Protection Act applies to these services as well, and if you cannot assure yourself that the service in question is within the EEA, you should avoid storing such data there.