Lets look at Chill Touch as an example. Its description states that it can be applied once per caster level among one or more creatures. Therefore, as a 5th level sorcerer, I can use Chill Touch 5 times per cast, spread among up to 5 creatures.
Under Combat->Cast a Spell->Touch Spells in Combat-> Holding a Charge:
Holding the Charge: If you don’t discharge the spell in the round when you cast the spell, you can hold the charge indefinitely. You can continue to make touch attacks round after round. If you touch anything or anyone while holding a charge, even unintentionally, the spell discharges. If you cast another spell, the touch spell dissipates. You can touch one friend as a standard action or up to six friends as a full-round action. Alternatively, you may make a normal unarmed attack (or an attack with a natural weapon) while holding a charge. In this case, you aren’t considered armed and you provoke attacks of opportunity as normal for the attack. If your unarmed attack or natural weapon attack normally doesn’t provoke attacks of opportunity, neither does this attack. If the attack hits, you deal normal damage for your unarmed attack or natural weapon and the spell discharges. If the attack misses, you are still holding the charge.
This implies to me that I could hold 5 Chill Touch charges that I can use on enemies across 5 melee touch attacks, which would take multiple rounds. However, under Magic->Spell Description->Duration->Touch Spells and Holding the Charge:
Some touch spells allow you to touch multiple targets as part of the spell. You can’t hold the charge of such a spell; you must touch all targets of the spell in the same round that you finish casting the spell.
This doesn't make any sense to me. As described in the first quote, a touch attack can only be applied to an enemy by performing a melee touch attack. You would have to be a really high level sorcerer to be able to make even more than one attack per round. It would make a spell like Chill Touch utterly useless in the face of other damage-dealing alternatives like Burning Hands or Shocking Grasp. It would only make sense if you could cast it once, and use it across multiple rounds, perhaps in conjunction with a melee attack with a weapon.
How do touch attacks with multiple targets normally work?
Best Answer
Using chill touch
The spell chill touch actually does work the way the question says it would make sense for the spell to work. Here's the skinny on employing the chill touch spell:
Round 1: Take a standard action to cast the spell chill touch. Afterward, take a free action to make a melee touch attack against a foe. Alternatively, take a move action to do something (like move up to your speed) then take a free action to make a melee touch attack against a foe. If the melee touch attack is successful, one chill touch charge is expended and the foe's dealt damage as per the description of the spell chill touch.
Round 2+: Take a standard action to make one melee touch attack to deliver a chill touch attack. Each successful melee touch attack expends one of your remaining chill touch charges and deals the foe damage as per the description of the spell chill touch. (You can also take a move action before or after the attack, too, but taking the full attack action is no help here; see below.)
Now if only it were that simple to explain why the chill touch spell works that way!
Why chill touch works that way
The Spell Description sections don't seem to be meant to be taken in isolation. On Magic on Spell Description on Range on Touch also says
(Emphases mine.) And on Combat on Cast a Spell on Touch Attacks in Combat describes how a caster touches unwilling targets! With Touch coming as it does before Spell Description on Duration on Touch Spells and Holding the Charge, the game seems to assume that the reader's perusing the Magic chapter in order and that the reader's keeping in mind that when Touch Spells and Holding the Charge says…
…here Touch Spells and Holding the Charge is still discussing touching willing targets.
In other words, when in Pathfinder on Magic on Duration on Touch Spells and Holding a Charge says, "Some touch spells allow you to touch multiple targets as part of the spell," it's not talking about touch spells that require one or more attack rolls but about spells that require touching an unresisting creature: one that's willing to be touched by the spell's caster, like the typical ally, unconscious creature (see Aiming a Spell on Target or Targets), or sleeping victim. Thus, be extension, to smack a conscious and mobile fool who doesn't want a chill touch smack requires the caster to make a melee touch attack just like the typical touch spell.
Then in 2017 the game made things even clearer with this FAQ exchange:
…And that pretty much locks a typical caster into delivering but a lone chill touch during the caster's turn.
Note: The chill touch spell—because it grants the caster multiple charges—is a particularly problematic touch spell as evidenced by these questions. This question and this even more relevant question (and Starwed's excellent answer to it!) may provide a greater understanding of this often-confusing spell.