The engine makes a ticking noise when started cold but goes away. What is it?

There's some wear on the valve train , a rod/lifter is worn . You can try mechanic in a can conditioner/thinner oil and it may help but it will only get worse . IMO

In a seven year old truck, if it has been well maintained, I wouldn't expect undue wear causing this. If it's really cold, this might just be slow moving oil to the valvetrain. If so, use oil filters with backflow preventers. Or maybe the oil level is really low. Fill the oil and use an additive that improves lubrication, like STP or Rislone. Otherwise have a mechanic review this.

It ticks on initial start up but is fine the rest of the day then it’s a lifter getting weak, now the right way to fix this would be to replace the cam and all the lifters with new ones. But I have seen backyarders just replace the bad lifter and get away with it, but they have no liability like a good shop who would do it right.

I’ve heard lots of engines doing the same thing , it’s a lifter . To replace it is quite expensive and then need to do them all. Keep your oil changed and as long as it runs like it should I would drive it.