DOSBox is intended for running DOS games. Your accounting app may work acceptably for your needs in official DOSBox, but be aware that this forum provides no support for apps if you run into problems. Using an unofficial build of DOSBox, such as Dominus suggests, may work better with certain kinds of apps, particularly those that use file-sharing and/or printing features of DOS.
A Google search for "microphone icon in bottom right of window" turns up pages suggesting that the icons are related to the NVIDIA GeForce Experience and info on how to disable them.