Auto answer
There are several options for auto answers.
Immediate auto-answer
1. Open Settings, then SIP Settings.
2. In Auto answer incoming call dropdown choose Always option:
When you have an incoming call it will be answered automatically without a sound notification.
Server-side auto-answer
SIP headers detected by Softphone.Pro are configured on the PBX.
1. Open Settings, then SIP Settings.
2. In Auto answer incoming call dropdown choose Accept server-side auto-answer.
Softphone.Pro will answer automatically only calls with the following fields in the SIP header: Call-Info: Auto Answer, Call-Info: answer-after=0 or X-AUTOANSWER: TRUE. In this case the ringtone does not sound.
Auto-answer with delay
See this article on how to configure Auto-answer with delay in Softphone.Pro.