You can actually have multiplicity in your class diagram using Creately. There are a couple of ways to specify the multiplicity.
- You can connect two classes and then select the line and double-click along it where you want the multiplicity to be placed (so at the ends of the connector) and you can type in the multiplicity desired.
- Alternatively, if you select a connector type such as 'Association' then the multiplicities will be added automatically and you can double click them to edit them.
This very basic example shows the multiplicities: