OP asked how to do it on the softphone application, not deskphone.Hi Infused,
Yes, you can Indeed, even though it's not documented.
Navigate to: C:\ProgramData\3CX\Instance1\Data\Http\Interface\provisioning\**********\logo
Depending on the phones you've got (we've got Snom 821/870's, I had to convert my logo into an XML file) then paste that document there with the phone's model number.
View attachment 5931
Reprovision & restart your phones, it should apply the logo from then onwards. It all depends on the type of phones you use, some phones like an image, where as some like code. Go on your manufacturers' website, see what it takes.
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.