You can sync a One Click Form from your HQ account to your child accounts. If the form includes the option to automatically add a complimentary credit to a contact's account upon signup (enabled under Advanced Options), you must ensure the correct credit options are mapped through Franchise Mapping.
After syncing the form, go to the Cogwheel in the top right corner of the screen > Settings > navigate to Mapped Values > Free Credits.
Then, map the credit accordingly.