Ella verbs is a Spanish conjugation app for mobile devices. It supports both Latin American and European Spanish.
When you first enter the app, it will ask you to identify your confidence level for a series of verb tenses, then it will place you in one of thirty levels. Each level explains a specific verb tense, then adds conjugation, translation, and timed multiple-choice activities. There is also a free conjugation dictionary — with a subscription, you can quiz yourself on each verb or create a custom quiz.
Conjugation guides will pop up when you answer questions incorrectly, and the quizzes are designed to test you on previous mistakes. Only the first six levels are free, but there is a three-day free trial if you would like to test the whole program.
If you don’t want to pay for an app, both SpanishDict and Conjuguemos are free options for Spanish verb conjugation activities. However, these resources won’t record which verbs you had difficulty with, so they are not as personalized.