Signal Privacy Settings

Go to Settings.

Set username

Tap on your profile pic > Username > Save

Account

Create your PIN > Create a secure PIN (1234 or 0987 is not a secure pin. Create with at least 6-8 numbers.)
Registration Lock: On (after PIN is created)

Linked devices

Remove any device you don't use.

Chats

Generate link previews: Off

Notifications

Messages

Show: Select whatever suits you

Privacy

Phone number

Who can see my number: Nobody

Messaging

Read receipts: Off
Typing indicators: Off

Disappearing messages

Default timer for new chats: Select whatever suits you
For enabling disappearing messages for existing chats:
- Go to a particular chat > Tap 3 dots on top > Disappearing messages

App security

Screen lock: On
Screen lock inactivity timeout: Enter whatever suits you
Screen security: On
Incognito keyboard: On

Payments

Payment lock: On

Advanced

Always relay calls: On (Call quality will be reduced, but it'll prevent your location from being exposed through your IP address to the other person on the call.)

Verify safety number

Go to a particular chat > Tap 3 dots on top > Chat settings > View safety number

Compare the numbers or scan the code. If you and the other person have the same numbers, the session is secure.

Tap Mark as verified.