Commercial Fixed Wing
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 21
Situational Awareness; Workload; Communication Breakdown; Distraction
Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Air Traffic Control Issued New Clearance
Procedure; Human Factors
I was working Ground 1 & 2; CD/FD; combined for the COVID operations.  There were quite a few aircraft taxiing out with arrivals interspersed.  When I heard Aircraft Y call for pushback; I had three to go behind them; so I spoke to all other aircraft before getting back to them.  When I got back to them; I corrected their climb via SID since they were only filed 11;000; and the LOA is initial 10;000.  I gave them pushback on A west ok K after the last in line; [behind] a second company aircraft.  About this time Aircraft X was rolling out to T on Runway XX Left with Gate XX.  I was planning a left turn on B to D; then A when they called.  A few other calls were done first; then I observed Aircraft X taxiing straight in K to A without having called.  I told them that was a bad plan since I had Aircraft Y with pushback clearance at K and A; and I would have liked to be able to exchange that traffic.  I concluded that Aircraft Y had not even started to push back; and simply gave Aircraft X taxi A for Gate XX.  I received nothing further from Aircraft Y.Do not taxi clear [off] the runway further than is necessary; until instructed to do so.
Tower Controller reported a ground communication issue resulting in a taxiway incursion.  Controller was working multiple positions including Ground 1 & 2 along with FD/CD.