Any project you contribute to in a positive manner will be a plus on your CV.
But if you are to make a choice like this Web Application Project or This Mobile App Project then it should come down to what you would like to do the most. E.g. if you like working with mobile apps then focus on that, it'll be a bigger plus if you apply for a job where you're gonna create mobile apps, and since you like that the most that's the job you want the most.
Below are some similar questions I've responded to, some of the CPians I respect the most has also given their input I highly suggest you read it.
Carrer advice & job progression[
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required guidance regarding job selection[
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