1.) Best file manager apps for Android
a) Solid Explorer
This is Solid Explorer File and Cloud Manager Please note that this is a 14 day trial version. If you own the Solid Explorer Unlocked you can use the premium.
It's feature-rich and highly accessible thanks to a crisp Material Design UI.
b) Amaze File Manager
Open Source, light and smooth - Based on Material Design guidelines - Basic features like cut, copy, delete, compress, extract etc. easily accessible. You can't access data on your Micro SD card through the drop down menu; you must use the file tree. Amaze doesn't support cloud storage.
2.) Best messenger apps for Android
WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Pure instant messaging — simple, fast, secure, and synced across all your devices. Over 100 million active users in two and a half years. The free app has end-to-end encryption, does group chats and is a pioneer of chatbots. Unlike some other messengers, you can use it on multiple devices