Can I Copyright Something I Made on Canva?

When it comes to Copyrights you need to understand a few things and you also need to keep in mind that I'm not a lawyer - so if you're serious about copyrighting something then your best bet would be to ask someone that actually knows what he talks about.

Can I Copyright Something I Made on Canva?

That being said, if you create something in Canva you own the rights to use it and unless you give other people permission - they don't have rights to use your work.

Now things get more complicated because Canva has stock images and content which they say you have copyright access and can use commercially - but you need to be sure that's actually the case because they get their content from 3rd party websites. 

To copyright a design or a logo or anything you want: as far as I know the tool you're using to create that design is irrelevant.
You can copyright a logo made in Paint. 

As long as you haven't used copyrighted content in the design you're intending to copyright yourself you should be able to do it even if your design was created in Canva.