Best Secure and professional level free apps for Android

Browser: Brave Browser (Open source), Tor Browser (Open source, Decentralised network), Google Chrome

Instant messenger: Signal Private Messenger (Open source, E2E Encryption)

Email: ProtonMail (Open source, E2E Encryption)

VPN: ProtonVPN (Open source, No log policy)

Video calling: Google Duo (E2E Encryption)

Cloud storage: MEGA storage by Mega LTD (Open source, E2E Encryption)

Search engine: DuckDuckGo.com (Open source, Doesn't track)

For International translation: PayPal

Office apps: Microsoft Office for Android

Photo editing: Google Snapseed, Adobe Lightroom for Android

Video player: VLC for Android (Open source, Adfree)

App store: F-Droid (Open source, For free open source audited apps)

Password manager: LastPass Password manager (AES encryption)

Music streaming:

Spotify (Person choice)

Bitrate: 160kbps free with ads (320kbps paid)

Format: AAC 

Collection: 40+ Million songs

JioSaavn 

Bitrate: 160kbps free with ads (320kbps paid)

Format: MP3

Collection: 50+ Million songs

Gaana 

Bitrate:  128kbps free with ads (320kbps paid)

Format: MP3

Collection: 30+ Million Songs