When trying to delete an app I hold it until it jiggles but there is no - sign to touch to delete

Please check: Settings - Screen Time - Content & Privacy Restrictions - iTunes & App Store Purchases - Deleting Apps = Allow. 

Also check which app you are trying to delete.

Certain default apps that come pre-installed cannot be deleted (for example, you cannot delete the Settings app)

Also, you are looking for an “X” symbol, NOT a - ( minus ) sign.