One of the best ways to evaluate a digital resource is to use the SAMR model. The table below explains the SAMR model really well.
The following graphic suggests a broad range of software and apps that you could use as, or to create, digital teaching resources. No tool is truly restricted to one category however. How you use a tool, the activity you construct around it and the amount of choice and agency you give your students has as much to do with the SAMR level your activity will reach.
The SAMR model is often presented as a bottom up process where Redefinition is the most desirable and Substitution barely useful. In reality, students need a range of activities. Asking them to create a document using a word processor may be practically the same as asking them to hand write or use a typewriter but it may be that the act of writing is the skill you want to focus on. If you are trying to teach your students to construct a narrative and you ask them to create an animated video that tells a story, you may find that your class spends a great deal of time learning to use animation software or a video editing app and very little time actually writing a narrative.
When choosing an app, software or any other kind of digital teaching tool such as a video, a simulation or even an interactive worksheet I have some steps you can follow and some criteria you can use evaluate them with. As you gain experience however, I expect that you will develop your own process and your own criteria, based on your school, your individual teaching style, the needs of your class and the individual needs of your students.
Note: When looking for a digital resource for a specific purpose you might find something amazing that changes how you want to present the outcome or even inspires you to redesign your whole lesson or unit of work! Don't be afraid to take risks and try it.