Put contact inside the app
Add a clear Help or Contact entry in the settings screen. If the only route is a website, many people will skip support and leave a bad review instead.
Collect device details automatically
Attach the app version, operating system and device model to each message. It saves a round of questions and lets you spot a bug that only affects one release or one phone.
Keep the form short
Typing on a phone is slow. Ask for a subject and a message, offer a screenshot upload and pre-fill the account email. Every extra field costs you some messages.
Answer app store reviews
Reply to reviews politely and point to a support route for anything specific. A thoughtful reply to a one-star review is read by everyone who looks at the listing afterwards.
Handle crashes and bugs separately
Tag bug reports with the version, link them to one tracking item and tell affected users when a fix ships. Replying that it is fixed in the new version is the best kind of support message.
Feed requests back to the product team
Count feature requests and complaints by theme each month. Mobile users often say exactly what is missing, and the list is a ready roadmap input.