Expansion by a factor of 1026 is equivalent to expanding an object 1 nanometer (10−9 m, about half the width of a molecule of DNA) in length to one approximately 10.6 light years (about 62 trillion miles).
According to general relativity, any vacuum state with non-zero energy density generates a repulsive force that leads to an expansion of space.
This expansion explains various properties of the current universe that are difficult to account for without such an inflationary epoch.
The rapid expansion of space meant that any potential elementary particles (or other "unwanted" artifacts, such as topological defects) remaining from the time before inflation were now distributed very thinly across the universe.
When the inflaton field reconfigured itself into the low-energy vacuum state we currently observe, the huge difference in potential energy was released in the form of a dense, hot mixture of quarks, anti-quarks and gluons as it entered the electroweak epoch.