Before access another PC remotely over the internet, it's necessary to have a look at Recipient Settings.  

On the main interface of AnyViewer, go to Settings and choose "Recipient".  Then, you can see the default settings of Recipient. 

Default Recipient

There are three options: Allow to accept remote control; Allow temporary security code; Set my security code.  The first two options are enabled by default. 

Enabling "Allow to accept remote control " means allowing this PC to receive a control request from another device and the request needs to be confirmed manually on this PC. 

Enabling "Allow temporary security code" is to allow to control this PC by inputting a temporary security code. You can send your partner the temporary security code for remote support.  The code changes every time the software restart.

Enabling "Set my security code" and set your security code manually. Then click "OK" to save the change. The Recipient can be accessed by inputting a security code. The security code set manually won't change if the software restart. 

Set Security Code

If "Allow to accept remote control" is disabled , this PC won't be accessed by sending  a remote control request; if the second options is disabled, this computer can't be accessed via inputting temporary code; if the third party is disbaled, this device can't be accessed by inputting security code.