How to turn off the mobile phone security warning

Take the OPPO R9S mobile phone as an example, and the closing method is as follows:

First, turn on the phone, find the "Settings" item on the desktop, and then click Enter.

Secondly, after entering the settings, find the column of "Other Settings" and click Enter.

3. After entering other settings, find the item "Security and Privacy" and click Enter.

Four, after entering the security and privacy, find the "unknown source" and open it.