Restrictions and Limitations for CiviSpark
The sign-up page says:


Store up to 2000 contacts
Send up to 5000 emails per month
Payments are only supported with three processors: PayPal, Stripe and iATS
The interface is available in many languages.
A few other configurations are disabled by default, such as Households and some Location Types
It is not possible to enable other extensions than the ones provided by default.


If you can't do something on Spark, it's worth clarifying on the Spark channel on Mattermost whether it is an intentional limitation or just a problem with your setup.