There are two possibilities which Phillips was alluding two here.

One, for most of Napoleon's military career, he was also the head of the French state. This meant that Napoleon's duties were far more than that of a general on campaign. He had to review developments within France and its empire even when in the field. This meant that Napoleon was weighing in on issues like grain production simultaneously when he was in the field. There was a large courier apparatus that maintained a connection between Napoleon and metropolitan France. While Napoleon did delegate authority considerable authority to a number of servitors when he was away from Paris, especially Cambacérès, he always expected detailed reports from his lieutenants no matter how far away he was from France.

The other possibility is that Napoleon's paperwork here was also martial in nature. Napoleon operated in what was a an embryonic form of the modern military staff. In this system, a commander would issue orders to a series of professional officers who would then convey these down to corps commanders. Despite popular history claims that Napoleon invented the modern staff system, the Grande Armée's staff did not quite function like the military staffs that emerged in the nineteenth century. The Emperor poked his nose into a lot of aspects of operations rather than delegating specific aspects to key officers. But Napoloen possessed a superb organizer and chief of staff in the form of Berthier for most of the Napoleonic Wars. Berthier had the ability to "translate" the volume of instructions- both written and oral- that emanated from Napoleon's headquarters into something that was more legible for Napoleon's marshals and generals. Berthier maintained a massive number of couriers who could carry orders to the field and reports back to headquarters. The run time for orders to reach the field from headquarters could reached about two hours when Berthier's system worked.

Of course, paperwork for running the French state or immediate military affairs is not contradictory and there is abundant evidence from Napoleon's staff and household that the Emperor liberally engaged in both forms of drudgery. The rise of the state built on paperwork was something that long predated Napoleon. The great seventeenth-century Spanish minister the Count-Duke of Olivares earned the unflattering nickname the "King's scarecrow" from his rivals because the Count-Duke always had reams of paper in his sleeves for his King to sign. But Napoleon's drive for centralization and amalgamation of supreme general in the field and head of state were somewhat unique among his contemporaries. This meant the amount of paperwork he produced and consumed was quite large compared to other generals of his era. To Napoleon's credit, he was mostly able to keep up on this correspondence. He had a prodigious memory and capacity for work and multi-tasking. But the system was always a problematic one prone to over-centralization and micromanagement. Civil servitors like Cambacérès or members of his household like Géraud Duroc were very capable lieutenants, but Napoleon's habits of management denuded them of initiative. By the same token, even Berthier could not always translate Napoleon's voluminous orders into something legible. The relationship between Napoleon and Berthier was also something that was less professional like it is in contemporary chiefs of staff and much more personal. A number of wags in the Grande Armée joked that Berthier was Napoleon's wife who eased the commander out of his moods and managed the military "household" like a proper French matron. Berthier's refusal to return to Napoleon during the Hundred Days and the Marshal's mysterious death denied Napoleon this vital element of his prior successes. One of the real problems the French faced at Waterloo was that Napoleon issued faulty and contradictory instructions to his subordinates. Berthier's replacement, Soult, lacked his predecessor's finesse in translating orders into reality. The Napoleonic scholar David Chandler actually used Napoleon's orders to Grouchy as an example for his students at Sandhurst of how not to delegate military operations to subordinates.

Napoleon may have been a genius, but running both a modern state and a modern army was more than just the orders of one man. The over-centralization of both the military and the government was one of the hallmarks of Napoleon's leadership and was one of several Achilles' heels embedded within the structure of the First Empire.

Sources

Chandler, David G. On the Napoleonic Wars: Collected Essays. London: Greenhill Books, 1999.

Horward, Donald D., and Michael V. Leggiere. Napoleon and the Operational Art of War: Essays in Honor of Donald D. Horward. Leiden: Brill, 2016.

Woloch, Isser. Napoleon and His Collaborators: The Making of a Dictatorship. New York: London : W.W. Norton, 2002.